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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>11.13. sqlite3 — DB-API 2.0 interface for SQLite databases — Python 2.7.18 documentation</title> <link rel="stylesheet" href="../_static/classic.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/language_data.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.18 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="12. 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Data Persistence</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-sqlite3"> <span id="sqlite3-db-api-2-0-interface-for-sqlite-databases"></span><h1>11.13. <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> — DB-API 2.0 interface for SQLite databases<a class="headerlink" href="#module-sqlite3" title="Permalink to this headline">¶</a></h1> <div class="versionadded"> <p><span class="versionmodified">New in version 2.5.</span></p> </div> <p>SQLite is a C library that provides a lightweight disk-based database that doesn’t require a separate server process and allows accessing the database using a nonstandard variant of the SQL query language. Some applications can use SQLite for internal data storage. It’s also possible to prototype an application using SQLite and then port the code to a larger database such as PostgreSQL or Oracle.</p> <p>The sqlite3 module was written by Gerhard Häring. It provides a SQL interface compliant with the DB-API 2.0 specification described by <span class="target" id="index-0"></span><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0249"><strong>PEP 249</strong></a>.</p> <p>To use the module, you must first create a <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> object that represents the database. Here the data will be stored in the <code class="file docutils literal notranslate"><span class="pre">example.db</span></code> file:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">conn</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s1">'example.db'</span><span class="p">)</span> </pre></div> </div> <p>You can also supply the special name <code class="docutils literal notranslate"><span class="pre">:memory:</span></code> to create a database in RAM.</p> <p>Once you have a <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a>, you can create a <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> object and call its <a class="reference internal" href="#sqlite3.Cursor.execute" title="sqlite3.Cursor.execute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">execute()</span></code></a> method to perform SQL commands:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">c</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="c1"># Create table</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'''CREATE TABLE stocks</span> <span class="s1"> (date text, trans text, symbol text, qty real, price real)'''</span><span class="p">)</span> <span class="c1"># Insert a row of data</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"INSERT INTO stocks VALUES ('2006-01-05','BUY','RHAT',100,35.14)"</span><span class="p">)</span> <span class="c1"># Save (commit) the changes</span> <span class="n">conn</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span> <span class="c1"># We can also close the connection if we are done with it.</span> <span class="c1"># Just be sure any changes have been committed or they will be lost.</span> <span class="n">conn</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> </pre></div> </div> <p>The data you’ve saved is persistent and is available in subsequent sessions:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">conn</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s1">'example.db'</span><span class="p">)</span> <span class="n">c</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> </pre></div> </div> <p>Usually your SQL operations will need to use values from Python variables. You shouldn’t assemble your query using Python’s string operations because doing so is insecure; it makes your program vulnerable to an SQL injection attack (see <a class="reference external" href="https://xkcd.com/327/">https://xkcd.com/327/</a> for humorous example of what can go wrong).</p> <p>Instead, use the DB-API’s parameter substitution. Put <code class="docutils literal notranslate"><span class="pre">?</span></code> as a placeholder wherever you want to use a value, and then provide a tuple of values as the second argument to the cursor’s <a class="reference internal" href="#sqlite3.Cursor.execute" title="sqlite3.Cursor.execute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">execute()</span></code></a> method. (Other database modules may use a different placeholder, such as <code class="docutils literal notranslate"><span class="pre">%s</span></code> or <code class="docutils literal notranslate"><span class="pre">:1</span></code>.) For example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1"># Never do this -- insecure!</span> <span class="n">symbol</span> <span class="o">=</span> <span class="s1">'RHAT'</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"SELECT * FROM stocks WHERE symbol = '</span><span class="si">%s</span><span class="s2">'"</span> <span class="o">%</span> <span class="n">symbol</span><span class="p">)</span> <span class="c1"># Do this instead</span> <span class="n">t</span> <span class="o">=</span> <span class="p">(</span><span class="s1">'RHAT'</span><span class="p">,)</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'SELECT * FROM stocks WHERE symbol=?'</span><span class="p">,</span> <span class="n">t</span><span class="p">)</span> <span class="nb">print</span> <span class="n">c</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="c1"># Larger example that inserts many records at a time</span> <span class="n">purchases</span> <span class="o">=</span> <span class="p">[(</span><span class="s1">'2006-03-28'</span><span class="p">,</span> <span class="s1">'BUY'</span><span class="p">,</span> <span class="s1">'IBM'</span><span class="p">,</span> <span class="mi">1000</span><span class="p">,</span> <span class="mf">45.00</span><span class="p">),</span> <span class="p">(</span><span class="s1">'2006-04-05'</span><span class="p">,</span> <span class="s1">'BUY'</span><span class="p">,</span> <span class="s1">'MSFT'</span><span class="p">,</span> <span class="mi">1000</span><span class="p">,</span> <span class="mf">72.00</span><span class="p">),</span> <span class="p">(</span><span class="s1">'2006-04-06'</span><span class="p">,</span> <span class="s1">'SELL'</span><span class="p">,</span> <span class="s1">'IBM'</span><span class="p">,</span> <span class="mi">500</span><span class="p">,</span> <span class="mf">53.00</span><span class="p">),</span> <span class="p">]</span> <span class="n">c</span><span class="o">.</span><span class="n">executemany</span><span class="p">(</span><span class="s1">'INSERT INTO stocks VALUES (?,?,?,?,?)'</span><span class="p">,</span> <span class="n">purchases</span><span class="p">)</span> </pre></div> </div> <p>To retrieve data after executing a SELECT statement, you can either treat the cursor as an <a class="reference internal" href="../glossary.html#term-iterator"><span class="xref std std-term">iterator</span></a>, call the cursor’s <a class="reference internal" href="#sqlite3.Cursor.fetchone" title="sqlite3.Cursor.fetchone"><code class="xref py py-meth docutils literal notranslate"><span class="pre">fetchone()</span></code></a> method to retrieve a single matching row, or call <a class="reference internal" href="#sqlite3.Cursor.fetchall" title="sqlite3.Cursor.fetchall"><code class="xref py py-meth docutils literal notranslate"><span class="pre">fetchall()</span></code></a> to get a list of the matching rows.</p> <p>This example uses the iterator form:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'SELECT * FROM stocks ORDER BY price'</span><span class="p">):</span> <span class="go"> print row</span> <span class="go">(u'2006-01-05', u'BUY', u'RHAT', 100, 35.14)</span> <span class="go">(u'2006-03-28', u'BUY', u'IBM', 1000, 45.0)</span> <span class="go">(u'2006-04-06', u'SELL', u'IBM', 500, 53.0)</span> <span class="go">(u'2006-04-05', u'BUY', u'MSFT', 1000, 72.0)</span> </pre></div> </div> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt><a class="reference external" href="https://github.com/ghaering/pysqlite">https://github.com/ghaering/pysqlite</a></dt> <dd>The pysqlite web page – sqlite3 is developed externally under the name “pysqlite”.</dd> <dt><a class="reference external" href="https://www.sqlite.org">https://www.sqlite.org</a></dt> <dd>The SQLite web page; the documentation describes the syntax and the available data types for the supported SQL dialect.</dd> <dt><a class="reference external" href="http://www.w3schools.com/sql/">http://www.w3schools.com/sql/</a></dt> <dd>Tutorial, reference and examples for learning SQL syntax.</dd> <dt><span class="target" id="index-1"></span><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0249"><strong>PEP 249</strong></a> - Database API Specification 2.0</dt> <dd>PEP written by Marc-André Lemburg.</dd> </dl> </div> <div class="section" id="module-functions-and-constants"> <span id="sqlite3-module-contents"></span><h2>11.13.1. Module functions and constants<a class="headerlink" href="#module-functions-and-constants" title="Permalink to this headline">¶</a></h2> <dl class="data"> <dt id="sqlite3.version"> <code class="descclassname">sqlite3.</code><code class="descname">version</code><a class="headerlink" href="#sqlite3.version" title="Permalink to this definition">¶</a></dt> <dd><p>The version number of this module, as a string. This is not the version of the SQLite library.</p> </dd></dl> <dl class="data"> <dt id="sqlite3.version_info"> <code class="descclassname">sqlite3.</code><code class="descname">version_info</code><a class="headerlink" href="#sqlite3.version_info" title="Permalink to this definition">¶</a></dt> <dd><p>The version number of this module, as a tuple of integers. This is not the version of the SQLite library.</p> </dd></dl> <dl class="data"> <dt id="sqlite3.sqlite_version"> <code class="descclassname">sqlite3.</code><code class="descname">sqlite_version</code><a class="headerlink" href="#sqlite3.sqlite_version" title="Permalink to this definition">¶</a></dt> <dd><p>The version number of the run-time SQLite library, as a string.</p> </dd></dl> <dl class="data"> <dt id="sqlite3.sqlite_version_info"> <code class="descclassname">sqlite3.</code><code class="descname">sqlite_version_info</code><a class="headerlink" href="#sqlite3.sqlite_version_info" title="Permalink to this definition">¶</a></dt> <dd><p>The version number of the run-time SQLite library, as a tuple of integers.</p> </dd></dl> <dl class="data"> <dt id="sqlite3.PARSE_DECLTYPES"> <code class="descclassname">sqlite3.</code><code class="descname">PARSE_DECLTYPES</code><a class="headerlink" href="#sqlite3.PARSE_DECLTYPES" title="Permalink to this definition">¶</a></dt> <dd><p>This constant is meant to be used with the <em>detect_types</em> parameter of the <a class="reference internal" href="#sqlite3.connect" title="sqlite3.connect"><code class="xref py py-func docutils literal notranslate"><span class="pre">connect()</span></code></a> function.</p> <p>Setting it makes the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module parse the declared type for each column it returns. It will parse out the first word of the declared type, i. e. for “integer primary key”, it will parse out “integer”, or for “number(10)” it will parse out “number”. Then for that column, it will look into the converters dictionary and use the converter function registered for that type there.</p> </dd></dl> <dl class="data"> <dt id="sqlite3.PARSE_COLNAMES"> <code class="descclassname">sqlite3.</code><code class="descname">PARSE_COLNAMES</code><a class="headerlink" href="#sqlite3.PARSE_COLNAMES" title="Permalink to this definition">¶</a></dt> <dd><p>This constant is meant to be used with the <em>detect_types</em> parameter of the <a class="reference internal" href="#sqlite3.connect" title="sqlite3.connect"><code class="xref py py-func docutils literal notranslate"><span class="pre">connect()</span></code></a> function.</p> <p>Setting this makes the SQLite interface parse the column name for each column it returns. It will look for a string formed [mytype] in there, and then decide that ‘mytype’ is the type of the column. It will try to find an entry of ‘mytype’ in the converters dictionary and then use the converter function found there to return the value. The column name found in <a class="reference internal" href="#sqlite3.Cursor.description" title="sqlite3.Cursor.description"><code class="xref py py-attr docutils literal notranslate"><span class="pre">Cursor.description</span></code></a> is only the first word of the column name, i. e. if you use something like <code class="docutils literal notranslate"><span class="pre">'as</span> <span class="pre">"x</span> <span class="pre">[datetime]"'</span></code> in your SQL, then we will parse out everything until the first blank for the column name: the column name would simply be “x”.</p> </dd></dl> <dl class="function"> <dt id="sqlite3.connect"> <code class="descclassname">sqlite3.</code><code class="descname">connect</code><span class="sig-paren">(</span><em>database</em><span class="optional">[</span>, <em>timeout</em>, <em>detect_types</em>, <em>isolation_level</em>, <em>check_same_thread</em>, <em>factory</em>, <em>cached_statements</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.connect" title="Permalink to this definition">¶</a></dt> <dd><p>Opens a connection to the SQLite database file <em>database</em>. You can use <code class="docutils literal notranslate"><span class="pre">":memory:"</span></code> to open a database connection to a database that resides in RAM instead of on disk.</p> <p>When a database is accessed by multiple connections, and one of the processes modifies the database, the SQLite database is locked until that transaction is committed. The <em>timeout</em> parameter specifies how long the connection should wait for the lock to go away until raising an exception. The default for the timeout parameter is 5.0 (five seconds).</p> <p>For the <em>isolation_level</em> parameter, please see the <a class="reference internal" href="#sqlite3.Connection.isolation_level" title="sqlite3.Connection.isolation_level"><code class="xref py py-attr docutils literal notranslate"><span class="pre">Connection.isolation_level</span></code></a> property of <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> objects.</p> <p>SQLite natively supports only the types TEXT, INTEGER, REAL, BLOB and NULL. If you want to use other types you must add support for them yourself. The <em>detect_types</em> parameter and the using custom <strong>converters</strong> registered with the module-level <a class="reference internal" href="#sqlite3.register_converter" title="sqlite3.register_converter"><code class="xref py py-func docutils literal notranslate"><span class="pre">register_converter()</span></code></a> function allow you to easily do that.</p> <p><em>detect_types</em> defaults to 0 (i. e. off, no type detection), you can set it to any combination of <a class="reference internal" href="#sqlite3.PARSE_DECLTYPES" title="sqlite3.PARSE_DECLTYPES"><code class="xref py py-const docutils literal notranslate"><span class="pre">PARSE_DECLTYPES</span></code></a> and <a class="reference internal" href="#sqlite3.PARSE_COLNAMES" title="sqlite3.PARSE_COLNAMES"><code class="xref py py-const docutils literal notranslate"><span class="pre">PARSE_COLNAMES</span></code></a> to turn type detection on.</p> <p>By default, the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module uses its <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> class for the connect call. You can, however, subclass the <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> class and make <a class="reference internal" href="#sqlite3.connect" title="sqlite3.connect"><code class="xref py py-func docutils literal notranslate"><span class="pre">connect()</span></code></a> use your class instead by providing your class for the <em>factory</em> parameter.</p> <p>Consult the section <a class="reference internal" href="#sqlite3-types"><span class="std std-ref">SQLite and Python types</span></a> of this manual for details.</p> <p>The <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module internally uses a statement cache to avoid SQL parsing overhead. If you want to explicitly set the number of statements that are cached for the connection, you can set the <em>cached_statements</em> parameter. The currently implemented default is to cache 100 statements.</p> </dd></dl> <dl class="function"> <dt id="sqlite3.register_converter"> <code class="descclassname">sqlite3.</code><code class="descname">register_converter</code><span class="sig-paren">(</span><em>typename</em>, <em>callable</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.register_converter" title="Permalink to this definition">¶</a></dt> <dd><p>Registers a callable to convert a bytestring from the database into a custom Python type. The callable will be invoked for all database values that are of the type <em>typename</em>. Confer the parameter <em>detect_types</em> of the <a class="reference internal" href="#sqlite3.connect" title="sqlite3.connect"><code class="xref py py-func docutils literal notranslate"><span class="pre">connect()</span></code></a> function for how the type detection works. Note that <em>typename</em> and the name of the type in your query are matched in case-insensitive manner.</p> </dd></dl> <dl class="function"> <dt id="sqlite3.register_adapter"> <code class="descclassname">sqlite3.</code><code class="descname">register_adapter</code><span class="sig-paren">(</span><em>type</em>, <em>callable</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.register_adapter" title="Permalink to this definition">¶</a></dt> <dd><p>Registers a callable to convert the custom Python type <em>type</em> into one of SQLite’s supported types. The callable <em>callable</em> accepts as single parameter the Python value, and must return a value of the following types: int, long, float, str (UTF-8 encoded), unicode or buffer.</p> </dd></dl> <dl class="function"> <dt id="sqlite3.complete_statement"> <code class="descclassname">sqlite3.</code><code class="descname">complete_statement</code><span class="sig-paren">(</span><em>sql</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.complete_statement" title="Permalink to this definition">¶</a></dt> <dd><p>Returns <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the string <em>sql</em> contains one or more complete SQL statements terminated by semicolons. It does not verify that the SQL is syntactically correct, only that there are no unclosed string literals and the statement is terminated by a semicolon.</p> <p>This can be used to build a shell for SQLite, as in the following example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1"># A minimal SQLite shell for experiments</span> <span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">isolation_level</span> <span class="o">=</span> <span class="kc">None</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">buffer</span> <span class="o">=</span> <span class="s2">""</span> <span class="nb">print</span> <span class="s2">"Enter your SQL commands to execute in sqlite3."</span> <span class="nb">print</span> <span class="s2">"Enter a blank line to exit."</span> <span class="k">while</span> <span class="kc">True</span><span class="p">:</span> <span class="n">line</span> <span class="o">=</span> <span class="n">raw_input</span><span class="p">()</span> <span class="k">if</span> <span class="n">line</span> <span class="o">==</span> <span class="s2">""</span><span class="p">:</span> <span class="k">break</span> <span class="n">buffer</span> <span class="o">+=</span> <span class="n">line</span> <span class="k">if</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">complete_statement</span><span class="p">(</span><span class="n">buffer</span><span class="p">):</span> <span class="k">try</span><span class="p">:</span> <span class="n">buffer</span> <span class="o">=</span> <span class="n">buffer</span><span class="o">.</span><span class="n">strip</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="n">buffer</span><span class="p">)</span> <span class="k">if</span> <span class="n">buffer</span><span class="o">.</span><span class="n">lstrip</span><span class="p">()</span><span class="o">.</span><span class="n">upper</span><span class="p">()</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="s2">"SELECT"</span><span class="p">):</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchall</span><span class="p">()</span> <span class="k">except</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">Error</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span> <span class="nb">print</span> <span class="s2">"An error occurred:"</span><span class="p">,</span> <span class="n">e</span><span class="o">.</span><span class="n">args</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="n">buffer</span> <span class="o">=</span> <span class="s2">""</span> <span class="n">con</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="sqlite3.enable_callback_tracebacks"> <code class="descclassname">sqlite3.</code><code class="descname">enable_callback_tracebacks</code><span class="sig-paren">(</span><em>flag</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.enable_callback_tracebacks" title="Permalink to this definition">¶</a></dt> <dd><p>By default you will not get any tracebacks in user-defined functions, aggregates, converters, authorizer callbacks etc. If you want to debug them, you can call this function with <em>flag</em> set to <code class="docutils literal notranslate"><span class="pre">True</span></code>. Afterwards, you will get tracebacks from callbacks on <code class="docutils literal notranslate"><span class="pre">sys.stderr</span></code>. Use <a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> to disable the feature again.</p> </dd></dl> </div> <div class="section" id="connection-objects"> <span id="sqlite3-connection-objects"></span><h2>11.13.2. Connection Objects<a class="headerlink" href="#connection-objects" title="Permalink to this headline">¶</a></h2> <dl class="class"> <dt id="sqlite3.Connection"> <em class="property">class </em><code class="descclassname">sqlite3.</code><code class="descname">Connection</code><a class="headerlink" href="#sqlite3.Connection" title="Permalink to this definition">¶</a></dt> <dd><p>A SQLite database connection has the following attributes and methods:</p> <dl class="attribute"> <dt id="sqlite3.Connection.isolation_level"> <code class="descname">isolation_level</code><a class="headerlink" href="#sqlite3.Connection.isolation_level" title="Permalink to this definition">¶</a></dt> <dd><p>Get or set the current isolation level. <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> for autocommit mode or one of “DEFERRED”, “IMMEDIATE” or “EXCLUSIVE”. See section <a class="reference internal" href="#sqlite3-controlling-transactions"><span class="std std-ref">Controlling Transactions</span></a> for a more detailed explanation.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.cursor"> <code class="descname">cursor</code><span class="sig-paren">(</span><em>factory=Cursor</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.cursor" title="Permalink to this definition">¶</a></dt> <dd><p>The cursor method accepts a single optional parameter <em>factory</em>. If supplied, this must be a callable returning an instance of <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> or its subclasses.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.commit"> <code class="descname">commit</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.commit" title="Permalink to this definition">¶</a></dt> <dd><p>This method commits the current transaction. If you don’t call this method, anything you did since the last call to <code class="docutils literal notranslate"><span class="pre">commit()</span></code> is not visible from other database connections. If you wonder why you don’t see the data you’ve written to the database, please check you didn’t forget to call this method.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.rollback"> <code class="descname">rollback</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.rollback" title="Permalink to this definition">¶</a></dt> <dd><p>This method rolls back any changes to the database since the last call to <a class="reference internal" href="#sqlite3.Connection.commit" title="sqlite3.Connection.commit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">commit()</span></code></a>.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.close" title="Permalink to this definition">¶</a></dt> <dd><p>This closes the database connection. Note that this does not automatically call <a class="reference internal" href="#sqlite3.Connection.commit" title="sqlite3.Connection.commit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">commit()</span></code></a>. If you just close your database connection without calling <a class="reference internal" href="#sqlite3.Connection.commit" title="sqlite3.Connection.commit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">commit()</span></code></a> first, your changes will be lost!</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.execute"> <code class="descname">execute</code><span class="sig-paren">(</span><em>sql</em><span class="optional">[</span>, <em>parameters</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.execute" title="Permalink to this definition">¶</a></dt> <dd><p>This is a nonstandard shortcut that creates an intermediate cursor object by calling the cursor method, then calls the cursor’s <a class="reference internal" href="#sqlite3.Cursor.execute" title="sqlite3.Cursor.execute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">execute</span></code></a> method with the parameters given.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.executemany"> <code class="descname">executemany</code><span class="sig-paren">(</span><em>sql</em><span class="optional">[</span>, <em>parameters</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.executemany" title="Permalink to this definition">¶</a></dt> <dd><p>This is a nonstandard shortcut that creates an intermediate cursor object by calling the cursor method, then calls the cursor’s <a class="reference internal" href="#sqlite3.Cursor.executemany" title="sqlite3.Cursor.executemany"><code class="xref py py-meth docutils literal notranslate"><span class="pre">executemany</span></code></a> method with the parameters given.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.executescript"> <code class="descname">executescript</code><span class="sig-paren">(</span><em>sql_script</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.executescript" title="Permalink to this definition">¶</a></dt> <dd><p>This is a nonstandard shortcut that creates an intermediate cursor object by calling the cursor method, then calls the cursor’s <a class="reference internal" href="#sqlite3.Cursor.executescript" title="sqlite3.Cursor.executescript"><code class="xref py py-meth docutils literal notranslate"><span class="pre">executescript</span></code></a> method with the parameters given.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.create_function"> <code class="descname">create_function</code><span class="sig-paren">(</span><em>name</em>, <em>num_params</em>, <em>func</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.create_function" title="Permalink to this definition">¶</a></dt> <dd><p>Creates a user-defined function that you can later use from within SQL statements under the function name <em>name</em>. <em>num_params</em> is the number of parameters the function accepts, and <em>func</em> is a Python callable that is called as the SQL function.</p> <p>The function can return any of the types supported by SQLite: unicode, str, int, long, float, buffer and <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p> <p>Example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="kn">import</span> <span class="nn">md5</span> <span class="k">def</span> <span class="nf">md5sum</span><span class="p">(</span><span class="n">t</span><span class="p">):</span> <span class="k">return</span> <span class="n">md5</span><span class="o">.</span><span class="n">md5</span><span class="p">(</span><span class="n">t</span><span class="p">)</span><span class="o">.</span><span class="n">hexdigest</span><span class="p">()</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">create_function</span><span class="p">(</span><span class="s2">"md5"</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="n">md5sum</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select md5(?)"</span><span class="p">,</span> <span class="p">(</span><span class="s2">"foo"</span><span class="p">,))</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> </pre></div> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.create_aggregate"> <code class="descname">create_aggregate</code><span class="sig-paren">(</span><em>name</em>, <em>num_params</em>, <em>aggregate_class</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.create_aggregate" title="Permalink to this definition">¶</a></dt> <dd><p>Creates a user-defined aggregate function.</p> <p>The aggregate class must implement a <code class="docutils literal notranslate"><span class="pre">step</span></code> method, which accepts the number of parameters <em>num_params</em>, and a <code class="docutils literal notranslate"><span class="pre">finalize</span></code> method which will return the final result of the aggregate.</p> <p>The <code class="docutils literal notranslate"><span class="pre">finalize</span></code> method can return any of the types supported by SQLite: unicode, str, int, long, float, buffer and <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p> <p>Example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">class</span> <span class="nc">MySum</span><span class="p">:</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">=</span> <span class="mi">0</span> <span class="k">def</span> <span class="nf">step</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">+=</span> <span class="n">value</span> <span class="k">def</span> <span class="nf">finalize</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">create_aggregate</span><span class="p">(</span><span class="s2">"mysum"</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="n">MySum</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table test(i)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into test(i) values (1)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into test(i) values (2)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select mysum(i) from test"</span><span class="p">)</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> </pre></div> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.create_collation"> <code class="descname">create_collation</code><span class="sig-paren">(</span><em>name</em>, <em>callable</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.create_collation" title="Permalink to this definition">¶</a></dt> <dd><p>Creates a collation with the specified <em>name</em> and <em>callable</em>. The callable will be passed two string arguments. It should return -1 if the first is ordered lower than the second, 0 if they are ordered equal and 1 if the first is ordered higher than the second. Note that this controls sorting (ORDER BY in SQL) so your comparisons don’t affect other SQL operations.</p> <p>Note that the callable will get its parameters as Python bytestrings, which will normally be encoded in UTF-8.</p> <p>The following example shows a custom collation that sorts “the wrong way”:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">def</span> <span class="nf">collate_reverse</span><span class="p">(</span><span class="n">string1</span><span class="p">,</span> <span class="n">string2</span><span class="p">):</span> <span class="k">return</span> <span class="o">-</span><span class="nb">cmp</span><span class="p">(</span><span class="n">string1</span><span class="p">,</span> <span class="n">string2</span><span class="p">)</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">create_collation</span><span class="p">(</span><span class="s2">"reverse"</span><span class="p">,</span> <span class="n">collate_reverse</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table test(x)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">executemany</span><span class="p">(</span><span class="s2">"insert into test(x) values (?)"</span><span class="p">,</span> <span class="p">[(</span><span class="s2">"a"</span><span class="p">,),</span> <span class="p">(</span><span class="s2">"b"</span><span class="p">,)])</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select x from test order by x collate reverse"</span><span class="p">)</span> <span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">cur</span><span class="p">:</span> <span class="nb">print</span> <span class="n">row</span> <span class="n">con</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> </pre></div> </div> <p>To remove a collation, call <code class="docutils literal notranslate"><span class="pre">create_collation</span></code> with <code class="docutils literal notranslate"><span class="pre">None</span></code> as callable:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">con</span><span class="o">.</span><span class="n">create_collation</span><span class="p">(</span><span class="s2">"reverse"</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span> </pre></div> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.interrupt"> <code class="descname">interrupt</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.interrupt" title="Permalink to this definition">¶</a></dt> <dd><p>You can call this method from a different thread to abort any queries that might be executing on the connection. The query will then abort and the caller will get an exception.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.set_authorizer"> <code class="descname">set_authorizer</code><span class="sig-paren">(</span><em>authorizer_callback</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.set_authorizer" title="Permalink to this definition">¶</a></dt> <dd><p>This routine registers a callback. The callback is invoked for each attempt to access a column of a table in the database. The callback should return <code class="xref py py-const docutils literal notranslate"><span class="pre">SQLITE_OK</span></code> if access is allowed, <code class="xref py py-const docutils literal notranslate"><span class="pre">SQLITE_DENY</span></code> if the entire SQL statement should be aborted with an error and <code class="xref py py-const docutils literal notranslate"><span class="pre">SQLITE_IGNORE</span></code> if the column should be treated as a NULL value. These constants are available in the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module.</p> <p>The first argument to the callback signifies what kind of operation is to be authorized. The second and third argument will be arguments or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> depending on the first argument. The 4th argument is the name of the database (“main”, “temp”, etc.) if applicable. The 5th argument is the name of the inner-most trigger or view that is responsible for the access attempt or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> if this access attempt is directly from input SQL code.</p> <p>Please consult the SQLite documentation about the possible values for the first argument and the meaning of the second and third argument depending on the first one. All necessary constants are available in the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.set_progress_handler"> <code class="descname">set_progress_handler</code><span class="sig-paren">(</span><em>handler</em>, <em>n</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.set_progress_handler" title="Permalink to this definition">¶</a></dt> <dd><p>This routine registers a callback. The callback is invoked for every <em>n</em> instructions of the SQLite virtual machine. This is useful if you want to get called from SQLite during long-running operations, for example to update a GUI.</p> <p>If you want to clear any previously installed progress handler, call the method with <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> for <em>handler</em>.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.6.</span></p> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.enable_load_extension"> <code class="descname">enable_load_extension</code><span class="sig-paren">(</span><em>enabled</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.enable_load_extension" title="Permalink to this definition">¶</a></dt> <dd><p>This routine allows/disallows the SQLite engine to load SQLite extensions from shared libraries. SQLite extensions can define new functions, aggregates or whole new virtual table implementations. One well-known extension is the fulltext-search extension distributed with SQLite.</p> <p>Loadable extensions are disabled by default. See <a class="footnote-reference" href="#f1" id="id1">[1]</a>.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.7.</span></p> </div> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="c1"># enable extension loading</span> <span class="n">con</span><span class="o">.</span><span class="n">enable_load_extension</span><span class="p">(</span><span class="kc">True</span><span class="p">)</span> <span class="c1"># Load the fulltext search extension</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select load_extension('./fts3.so')"</span><span class="p">)</span> <span class="c1"># alternatively you can load the extension using an API call:</span> <span class="c1"># con.load_extension("./fts3.so")</span> <span class="c1"># disable extension loading again</span> <span class="n">con</span><span class="o">.</span><span class="n">enable_load_extension</span><span class="p">(</span><span class="kc">False</span><span class="p">)</span> <span class="c1"># example from SQLite wiki</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create virtual table recipe using fts3(name, ingredients)"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">executescript</span><span class="p">(</span><span class="s2">"""</span> <span class="s2"> insert into recipe (name, ingredients) values ('broccoli stew', 'broccoli peppers cheese tomatoes');</span> <span class="s2"> insert into recipe (name, ingredients) values ('pumpkin stew', 'pumpkin onions garlic celery');</span> <span class="s2"> insert into recipe (name, ingredients) values ('broccoli pie', 'broccoli cheese onions flour');</span> <span class="s2"> insert into recipe (name, ingredients) values ('pumpkin pie', 'pumpkin sugar flour butter');</span> <span class="s2"> """</span><span class="p">)</span> <span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select rowid, name, ingredients from recipe where name match 'pie'"</span><span class="p">):</span> <span class="nb">print</span> <span class="n">row</span> </pre></div> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Connection.load_extension"> <code class="descname">load_extension</code><span class="sig-paren">(</span><em>path</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Connection.load_extension" title="Permalink to this definition">¶</a></dt> <dd><p>This routine loads a SQLite extension from a shared library. You have to enable extension loading with <a class="reference internal" href="#sqlite3.Connection.enable_load_extension" title="sqlite3.Connection.enable_load_extension"><code class="xref py py-meth docutils literal notranslate"><span class="pre">enable_load_extension()</span></code></a> before you can use this routine.</p> <p>Loadable extensions are disabled by default. See <a class="footnote-reference" href="#f1" id="id2">[1]</a>.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.7.</span></p> </div> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Connection.row_factory"> <code class="descname">row_factory</code><a class="headerlink" href="#sqlite3.Connection.row_factory" title="Permalink to this definition">¶</a></dt> <dd><p>You can change this attribute to a callable that accepts the cursor and the original row as a tuple and will return the real result row. This way, you can implement more advanced ways of returning results, such as returning an object that can also access columns by name.</p> <p>Example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">def</span> <span class="nf">dict_factory</span><span class="p">(</span><span class="n">cursor</span><span class="p">,</span> <span class="n">row</span><span class="p">):</span> <span class="n">d</span> <span class="o">=</span> <span class="p">{}</span> <span class="k">for</span> <span class="n">idx</span><span class="p">,</span> <span class="n">col</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">cursor</span><span class="o">.</span><span class="n">description</span><span class="p">):</span> <span class="n">d</span><span class="p">[</span><span class="n">col</span><span class="p">[</span><span class="mi">0</span><span class="p">]]</span> <span class="o">=</span> <span class="n">row</span><span class="p">[</span><span class="n">idx</span><span class="p">]</span> <span class="k">return</span> <span class="n">d</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">row_factory</span> <span class="o">=</span> <span class="n">dict_factory</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select 1 as a"</span><span class="p">)</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="s2">"a"</span><span class="p">]</span> </pre></div> </div> <p>If returning a tuple doesn’t suffice and you want name-based access to columns, you should consider setting <a class="reference internal" href="#sqlite3.Connection.row_factory" title="sqlite3.Connection.row_factory"><code class="xref py py-attr docutils literal notranslate"><span class="pre">row_factory</span></code></a> to the highly-optimized <a class="reference internal" href="#sqlite3.Row" title="sqlite3.Row"><code class="xref py py-class docutils literal notranslate"><span class="pre">sqlite3.Row</span></code></a> type. <a class="reference internal" href="#sqlite3.Row" title="sqlite3.Row"><code class="xref py py-class docutils literal notranslate"><span class="pre">Row</span></code></a> provides both index-based and case-insensitive name-based access to columns with almost no memory overhead. It will probably be better than your own custom dictionary-based approach or even a db_row based solution.</p> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Connection.text_factory"> <code class="descname">text_factory</code><a class="headerlink" href="#sqlite3.Connection.text_factory" title="Permalink to this definition">¶</a></dt> <dd><p>Using this attribute you can control what objects are returned for the <code class="docutils literal notranslate"><span class="pre">TEXT</span></code> data type. By default, this attribute is set to <a class="reference internal" href="functions.html#unicode" title="unicode"><code class="xref py py-class docutils literal notranslate"><span class="pre">unicode</span></code></a> and the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module will return Unicode objects for <code class="docutils literal notranslate"><span class="pre">TEXT</span></code>. If you want to return bytestrings instead, you can set it to <a class="reference internal" href="functions.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a>.</p> <p>For efficiency reasons, there’s also a way to return Unicode objects only for non-ASCII data, and bytestrings otherwise. To activate it, set this attribute to <code class="xref py py-const docutils literal notranslate"><span class="pre">sqlite3.OptimizedUnicode</span></code>.</p> <p>You can also set it to any other callable that accepts a single bytestring parameter and returns the resulting object.</p> <p>See the following example code for illustration:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">AUSTRIA</span> <span class="o">=</span> <span class="sa">u</span><span class="s2">"</span><span class="se">\xd6</span><span class="s2">sterreich"</span> <span class="c1"># by default, rows are returned as Unicode</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="n">AUSTRIA</span><span class="p">,))</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="k">assert</span> <span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">==</span> <span class="n">AUSTRIA</span> <span class="c1"># but we can make sqlite3 always return bytestrings ...</span> <span class="n">con</span><span class="o">.</span><span class="n">text_factory</span> <span class="o">=</span> <span class="nb">str</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="n">AUSTRIA</span><span class="p">,))</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="k">assert</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span> <span class="ow">is</span> <span class="nb">str</span> <span class="c1"># the bytestrings will be encoded in UTF-8, unless you stored garbage in the</span> <span class="c1"># database ...</span> <span class="k">assert</span> <span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">==</span> <span class="n">AUSTRIA</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">"utf-8"</span><span class="p">)</span> <span class="c1"># we can also implement a custom text_factory ...</span> <span class="c1"># here we implement one that will ignore Unicode characters that cannot be</span> <span class="c1"># decoded from UTF-8</span> <span class="n">con</span><span class="o">.</span><span class="n">text_factory</span> <span class="o">=</span> <span class="k">lambda</span> <span class="n">x</span><span class="p">:</span> <span class="n">unicode</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="s2">"utf-8"</span><span class="p">,</span> <span class="s2">"ignore"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="s2">"this is latin1 and would normally create errors"</span> <span class="o">+</span> <span class="sa">u</span><span class="s2">"</span><span class="se">\xe4\xf6\xfc</span><span class="s2">"</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">"latin1"</span><span class="p">),))</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="k">assert</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span> <span class="ow">is</span> <span class="n">unicode</span> <span class="c1"># sqlite3 offers a built-in optimized text_factory that will return bytestring</span> <span class="c1"># objects, if the data is in ASCII only, and otherwise return unicode objects</span> <span class="n">con</span><span class="o">.</span><span class="n">text_factory</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">OptimizedUnicode</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="n">AUSTRIA</span><span class="p">,))</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="k">assert</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span> <span class="ow">is</span> <span class="n">unicode</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="s2">"Germany"</span><span class="p">,))</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="k">assert</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span> <span class="ow">is</span> <span class="nb">str</span> </pre></div> </div> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Connection.total_changes"> <code class="descname">total_changes</code><a class="headerlink" href="#sqlite3.Connection.total_changes" title="Permalink to this definition">¶</a></dt> <dd><p>Returns the total number of database rows that have been modified, inserted, or deleted since the database connection was opened.</p> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Connection.iterdump"> <code class="descname">iterdump</code><a class="headerlink" href="#sqlite3.Connection.iterdump" title="Permalink to this definition">¶</a></dt> <dd><p>Returns an iterator to dump the database in an SQL text format. Useful when saving an in-memory database for later restoration. This function provides the same capabilities as the <kbd class="kbd docutils literal notranslate">.dump</kbd> command in the <strong class="program">sqlite3</strong> shell.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.6.</span></p> </div> <p>Example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1"># Convert file existing_db.db to SQL dump file dump.sql</span> <span class="kn">import</span> <span class="nn">sqlite3</span><span class="o">,</span> <span class="nn">os</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s1">'existing_db.db'</span><span class="p">)</span> <span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s1">'dump.sql'</span><span class="p">,</span> <span class="s1">'w'</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span> <span class="k">for</span> <span class="n">line</span> <span class="ow">in</span> <span class="n">con</span><span class="o">.</span><span class="n">iterdump</span><span class="p">():</span> <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="s1">'</span><span class="si">%s</span><span class="se">\n</span><span class="s1">'</span> <span class="o">%</span> <span class="n">line</span><span class="p">)</span> </pre></div> </div> </dd></dl> </dd></dl> </div> <div class="section" id="cursor-objects"> <span id="sqlite3-cursor-objects"></span><h2>11.13.3. Cursor Objects<a class="headerlink" href="#cursor-objects" title="Permalink to this headline">¶</a></h2> <dl class="class"> <dt id="sqlite3.Cursor"> <em class="property">class </em><code class="descclassname">sqlite3.</code><code class="descname">Cursor</code><a class="headerlink" href="#sqlite3.Cursor" title="Permalink to this definition">¶</a></dt> <dd><p>A <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> instance has the following attributes and methods.</p> <dl class="method"> <dt id="sqlite3.Cursor.execute"> <code class="descname">execute</code><span class="sig-paren">(</span><em>sql</em><span class="optional">[</span>, <em>parameters</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Cursor.execute" title="Permalink to this definition">¶</a></dt> <dd><p>Executes an SQL statement. The SQL statement may be parameterized (i. e. placeholders instead of SQL literals). The <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module supports two kinds of placeholders: question marks (qmark style) and named placeholders (named style).</p> <p>Here’s an example of both styles:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table people (name_last, age)"</span><span class="p">)</span> <span class="n">who</span> <span class="o">=</span> <span class="s2">"Yeltsin"</span> <span class="n">age</span> <span class="o">=</span> <span class="mi">72</span> <span class="c1"># This is the qmark style:</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into people values (?, ?)"</span><span class="p">,</span> <span class="p">(</span><span class="n">who</span><span class="p">,</span> <span class="n">age</span><span class="p">))</span> <span class="c1"># And this is the named style:</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select * from people where name_last=:who and age=:age"</span><span class="p">,</span> <span class="p">{</span><span class="s2">"who"</span><span class="p">:</span> <span class="n">who</span><span class="p">,</span> <span class="s2">"age"</span><span class="p">:</span> <span class="n">age</span><span class="p">})</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> </pre></div> </div> <p><a class="reference internal" href="#sqlite3.Cursor.execute" title="sqlite3.Cursor.execute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">execute()</span></code></a> will only execute a single SQL statement. If you try to execute more than one statement with it, it will raise a Warning. Use <a class="reference internal" href="#sqlite3.Cursor.executescript" title="sqlite3.Cursor.executescript"><code class="xref py py-meth docutils literal notranslate"><span class="pre">executescript()</span></code></a> if you want to execute multiple SQL statements with one call.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Cursor.executemany"> <code class="descname">executemany</code><span class="sig-paren">(</span><em>sql</em>, <em>seq_of_parameters</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Cursor.executemany" title="Permalink to this definition">¶</a></dt> <dd><p>Executes an SQL command against all parameter sequences or mappings found in the sequence <em>sql</em>. The <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module also allows using an <a class="reference internal" href="../glossary.html#term-iterator"><span class="xref std std-term">iterator</span></a> yielding parameters instead of a sequence.</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">class</span> <span class="nc">IterChars</span><span class="p">:</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">=</span> <span class="nb">ord</span><span class="p">(</span><span class="s1">'a'</span><span class="p">)</span> <span class="k">def</span> <span class="nf">__iter__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="bp">self</span> <span class="k">def</span> <span class="nf">next</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">></span> <span class="nb">ord</span><span class="p">(</span><span class="s1">'z'</span><span class="p">):</span> <span class="k">raise</span> <span class="ne">StopIteration</span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">+=</span> <span class="mi">1</span> <span class="k">return</span> <span class="p">(</span><span class="nb">chr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">-</span> <span class="mi">1</span><span class="p">),)</span> <span class="c1"># this is a 1-tuple</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table characters(c)"</span><span class="p">)</span> <span class="n">theIter</span> <span class="o">=</span> <span class="n">IterChars</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">executemany</span><span class="p">(</span><span class="s2">"insert into characters(c) values (?)"</span><span class="p">,</span> <span class="n">theIter</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select c from characters"</span><span class="p">)</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchall</span><span class="p">()</span> </pre></div> </div> <p>Here’s a shorter example using a <a class="reference internal" href="../glossary.html#term-generator"><span class="xref std std-term">generator</span></a>:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="kn">import</span> <span class="nn">string</span> <span class="k">def</span> <span class="nf">char_generator</span><span class="p">():</span> <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="n">string</span><span class="o">.</span><span class="n">lowercase</span><span class="p">:</span> <span class="k">yield</span> <span class="p">(</span><span class="n">c</span><span class="p">,)</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table characters(c)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">executemany</span><span class="p">(</span><span class="s2">"insert into characters(c) values (?)"</span><span class="p">,</span> <span class="n">char_generator</span><span class="p">())</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select c from characters"</span><span class="p">)</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchall</span><span class="p">()</span> </pre></div> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Cursor.executescript"> <code class="descname">executescript</code><span class="sig-paren">(</span><em>sql_script</em><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Cursor.executescript" title="Permalink to this definition">¶</a></dt> <dd><p>This is a nonstandard convenience method for executing multiple SQL statements at once. It issues a <code class="docutils literal notranslate"><span class="pre">COMMIT</span></code> statement first, then executes the SQL script it gets as a parameter.</p> <p><em>sql_script</em> can be a bytestring or a Unicode string.</p> <p>Example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">executescript</span><span class="p">(</span><span class="s2">"""</span> <span class="s2"> create table person(</span> <span class="s2"> firstname,</span> <span class="s2"> lastname,</span> <span class="s2"> age</span> <span class="s2"> );</span> <span class="s2"> create table book(</span> <span class="s2"> title,</span> <span class="s2"> author,</span> <span class="s2"> published</span> <span class="s2"> );</span> <span class="s2"> insert into book(title, author, published)</span> <span class="s2"> values (</span> <span class="s2"> 'Dirk Gently''s Holistic Detective Agency',</span> <span class="s2"> 'Douglas Adams',</span> <span class="s2"> 1987</span> <span class="s2"> );</span> <span class="s2"> """</span><span class="p">)</span> </pre></div> </div> </dd></dl> <dl class="method"> <dt id="sqlite3.Cursor.fetchone"> <code class="descname">fetchone</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Cursor.fetchone" title="Permalink to this definition">¶</a></dt> <dd><p>Fetches the next row of a query result set, returning a single sequence, or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> when no more data is available.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Cursor.fetchmany"> <code class="descname">fetchmany</code><span class="sig-paren">(</span><span class="optional">[</span><em>size=cursor.arraysize</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Cursor.fetchmany" title="Permalink to this definition">¶</a></dt> <dd><p>Fetches the next set of rows of a query result, returning a list. An empty list is returned when no more rows are available.</p> <p>The number of rows to fetch per call is specified by the <em>size</em> parameter. If it is not given, the cursor’s arraysize determines the number of rows to be fetched. The method should try to fetch as many rows as indicated by the size parameter. If this is not possible due to the specified number of rows not being available, fewer rows may be returned.</p> <p>Note there are performance considerations involved with the <em>size</em> parameter. For optimal performance, it is usually best to use the arraysize attribute. If the <em>size</em> parameter is used, then it is best for it to retain the same value from one <a class="reference internal" href="#sqlite3.Cursor.fetchmany" title="sqlite3.Cursor.fetchmany"><code class="xref py py-meth docutils literal notranslate"><span class="pre">fetchmany()</span></code></a> call to the next.</p> </dd></dl> <dl class="method"> <dt id="sqlite3.Cursor.fetchall"> <code class="descname">fetchall</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Cursor.fetchall" title="Permalink to this definition">¶</a></dt> <dd><p>Fetches all (remaining) rows of a query result, returning a list. Note that the cursor’s arraysize attribute can affect the performance of this operation. An empty list is returned when no rows are available.</p> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Cursor.rowcount"> <code class="descname">rowcount</code><a class="headerlink" href="#sqlite3.Cursor.rowcount" title="Permalink to this definition">¶</a></dt> <dd><p>Although the <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> class of the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module implements this attribute, the database engine’s own support for the determination of “rows affected”/”rows selected” is quirky.</p> <p>For <a class="reference internal" href="#sqlite3.Cursor.executemany" title="sqlite3.Cursor.executemany"><code class="xref py py-meth docutils literal notranslate"><span class="pre">executemany()</span></code></a> statements, the number of modifications are summed up into <a class="reference internal" href="#sqlite3.Cursor.rowcount" title="sqlite3.Cursor.rowcount"><code class="xref py py-attr docutils literal notranslate"><span class="pre">rowcount</span></code></a>.</p> <p>As required by the Python DB API Spec, the <a class="reference internal" href="#sqlite3.Cursor.rowcount" title="sqlite3.Cursor.rowcount"><code class="xref py py-attr docutils literal notranslate"><span class="pre">rowcount</span></code></a> attribute “is -1 in case no <code class="docutils literal notranslate"><span class="pre">executeXX()</span></code> has been performed on the cursor or the rowcount of the last operation is not determinable by the interface”. This includes <code class="docutils literal notranslate"><span class="pre">SELECT</span></code> statements because we cannot determine the number of rows a query produced until all rows were fetched.</p> <p>With SQLite versions before 3.6.5, <a class="reference internal" href="#sqlite3.Cursor.rowcount" title="sqlite3.Cursor.rowcount"><code class="xref py py-attr docutils literal notranslate"><span class="pre">rowcount</span></code></a> is set to 0 if you make a <code class="docutils literal notranslate"><span class="pre">DELETE</span> <span class="pre">FROM</span> <span class="pre">table</span></code> without any condition.</p> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Cursor.lastrowid"> <code class="descname">lastrowid</code><a class="headerlink" href="#sqlite3.Cursor.lastrowid" title="Permalink to this definition">¶</a></dt> <dd><p>This read-only attribute provides the rowid of the last modified row. It is only set if you issued an <code class="docutils literal notranslate"><span class="pre">INSERT</span></code> statement using the <a class="reference internal" href="#sqlite3.Cursor.execute" title="sqlite3.Cursor.execute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">execute()</span></code></a> method. For operations other than <code class="docutils literal notranslate"><span class="pre">INSERT</span></code> or when <a class="reference internal" href="#sqlite3.Cursor.executemany" title="sqlite3.Cursor.executemany"><code class="xref py py-meth docutils literal notranslate"><span class="pre">executemany()</span></code></a> is called, <a class="reference internal" href="#sqlite3.Cursor.lastrowid" title="sqlite3.Cursor.lastrowid"><code class="xref py py-attr docutils literal notranslate"><span class="pre">lastrowid</span></code></a> is set to <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>.</p> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Cursor.description"> <code class="descname">description</code><a class="headerlink" href="#sqlite3.Cursor.description" title="Permalink to this definition">¶</a></dt> <dd><p>This read-only attribute provides the column names of the last query. To remain compatible with the Python DB API, it returns a 7-tuple for each column where the last six items of each tuple are <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>.</p> <p>It is set for <code class="docutils literal notranslate"><span class="pre">SELECT</span></code> statements without any matching rows as well.</p> </dd></dl> <dl class="attribute"> <dt id="sqlite3.Cursor.connection"> <code class="descname">connection</code><a class="headerlink" href="#sqlite3.Cursor.connection" title="Permalink to this definition">¶</a></dt> <dd><p>This read-only attribute provides the SQLite database <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> used by the <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> object. A <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> object created by calling <a class="reference internal" href="#sqlite3.Connection.cursor" title="sqlite3.Connection.cursor"><code class="xref py py-meth docutils literal notranslate"><span class="pre">con.cursor()</span></code></a> will have a <a class="reference internal" href="#sqlite3.Cursor.connection" title="sqlite3.Cursor.connection"><code class="xref py py-attr docutils literal notranslate"><span class="pre">connection</span></code></a> attribute that refers to <em>con</em>:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">cur</span><span class="o">.</span><span class="n">connection</span> <span class="o">==</span> <span class="n">con</span> <span class="go">True</span> </pre></div> </div> </dd></dl> </dd></dl> </div> <div class="section" id="row-objects"> <span id="sqlite3-row-objects"></span><h2>11.13.4. Row Objects<a class="headerlink" href="#row-objects" title="Permalink to this headline">¶</a></h2> <dl class="class"> <dt id="sqlite3.Row"> <em class="property">class </em><code class="descclassname">sqlite3.</code><code class="descname">Row</code><a class="headerlink" href="#sqlite3.Row" title="Permalink to this definition">¶</a></dt> <dd><p>A <a class="reference internal" href="#sqlite3.Row" title="sqlite3.Row"><code class="xref py py-class docutils literal notranslate"><span class="pre">Row</span></code></a> instance serves as a highly optimized <a class="reference internal" href="#sqlite3.Connection.row_factory" title="sqlite3.Connection.row_factory"><code class="xref py py-attr docutils literal notranslate"><span class="pre">row_factory</span></code></a> for <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> objects. It tries to mimic a tuple in most of its features.</p> <p>It supports mapping access by column name and index, iteration, representation, equality testing and <a class="reference internal" href="functions.html#len" title="len"><code class="xref py py-func docutils literal notranslate"><span class="pre">len()</span></code></a>.</p> <p>If two <a class="reference internal" href="#sqlite3.Row" title="sqlite3.Row"><code class="xref py py-class docutils literal notranslate"><span class="pre">Row</span></code></a> objects have exactly the same columns and their members are equal, they compare equal.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.6: </span>Added iteration and equality (hashability).</p> </div> <dl class="method"> <dt id="sqlite3.Row.keys"> <code class="descname">keys</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#sqlite3.Row.keys" title="Permalink to this definition">¶</a></dt> <dd><p>This method returns a list of column names. Immediately after a query, it is the first member of each tuple in <a class="reference internal" href="#sqlite3.Cursor.description" title="sqlite3.Cursor.description"><code class="xref py py-attr docutils literal notranslate"><span class="pre">Cursor.description</span></code></a>.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.6.</span></p> </div> </dd></dl> </dd></dl> <p>Let’s assume we initialize a table as in the example given above:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">conn</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">c</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'''create table stocks</span> <span class="s1">(date text, trans text, symbol text,</span> <span class="s1"> qty real, price real)'''</span><span class="p">)</span> <span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"""insert into stocks</span> <span class="s2"> values ('2006-01-05','BUY','RHAT',100,35.14)"""</span><span class="p">)</span> <span class="n">conn</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span> <span class="n">c</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> </pre></div> </div> <p>Now we plug <a class="reference internal" href="#sqlite3.Row" title="sqlite3.Row"><code class="xref py py-class docutils literal notranslate"><span class="pre">Row</span></code></a> in:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">conn</span><span class="o">.</span><span class="n">row_factory</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">Row</span> <span class="gp">>>> </span><span class="n">c</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">c</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'select * from stocks'</span><span class="p">)</span> <span class="go"><sqlite3.Cursor object at 0x7f4e7dd8fa80></span> <span class="gp">>>> </span><span class="n">r</span> <span class="o">=</span> <span class="n">c</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="gp">>>> </span><span class="nb">type</span><span class="p">(</span><span class="n">r</span><span class="p">)</span> <span class="go"><type 'sqlite3.Row'></span> <span class="gp">>>> </span><span class="n">r</span> <span class="go">(u'2006-01-05', u'BUY', u'RHAT', 100.0, 35.14)</span> <span class="gp">>>> </span><span class="nb">len</span><span class="p">(</span><span class="n">r</span><span class="p">)</span> <span class="go">5</span> <span class="gp">>>> </span><span class="n">r</span><span class="p">[</span><span class="mi">2</span><span class="p">]</span> <span class="go">u'RHAT'</span> <span class="gp">>>> </span><span class="n">r</span><span class="o">.</span><span class="n">keys</span><span class="p">()</span> <span class="go">['date', 'trans', 'symbol', 'qty', 'price']</span> <span class="gp">>>> </span><span class="n">r</span><span class="p">[</span><span class="s1">'qty'</span><span class="p">]</span> <span class="go">100.0</span> <span class="gp">>>> </span><span class="k">for</span> <span class="n">member</span> <span class="ow">in</span> <span class="n">r</span><span class="p">:</span> <span class="gp">... </span> <span class="nb">print</span> <span class="n">member</span> <span class="gp">...</span> <span class="go">2006-01-05</span> <span class="go">BUY</span> <span class="go">RHAT</span> <span class="go">100.0</span> <span class="go">35.14</span> </pre></div> </div> </div> <div class="section" id="sqlite-and-python-types"> <span id="sqlite3-types"></span><h2>11.13.5. SQLite and Python types<a class="headerlink" href="#sqlite-and-python-types" title="Permalink to this headline">¶</a></h2> <div class="section" id="introduction"> <h3>11.13.5.1. Introduction<a class="headerlink" href="#introduction" title="Permalink to this headline">¶</a></h3> <p>SQLite natively supports the following types: <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, <code class="docutils literal notranslate"><span class="pre">INTEGER</span></code>, <code class="docutils literal notranslate"><span class="pre">REAL</span></code>, <code class="docutils literal notranslate"><span class="pre">TEXT</span></code>, <code class="docutils literal notranslate"><span class="pre">BLOB</span></code>.</p> <p>The following Python types can thus be sent to SQLite without any problem:</p> <table border="1" class="docutils"> <colgroup> <col width="69%" /> <col width="31%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Python type</th> <th class="head">SQLite type</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a></td> <td><code class="docutils literal notranslate"><span class="pre">NULL</span></code></td> </tr> <tr class="row-odd"><td><a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a></td> <td><code class="docutils literal notranslate"><span class="pre">INTEGER</span></code></td> </tr> <tr class="row-even"><td><a class="reference internal" href="functions.html#long" title="long"><code class="xref py py-class docutils literal notranslate"><span class="pre">long</span></code></a></td> <td><code class="docutils literal notranslate"><span class="pre">INTEGER</span></code></td> </tr> <tr class="row-odd"><td><a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a></td> <td><code class="docutils literal notranslate"><span class="pre">REAL</span></code></td> </tr> <tr class="row-even"><td><a class="reference internal" href="functions.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a> (UTF8-encoded)</td> <td><code class="docutils literal notranslate"><span class="pre">TEXT</span></code></td> </tr> <tr class="row-odd"><td><a class="reference internal" href="functions.html#unicode" title="unicode"><code class="xref py py-class docutils literal notranslate"><span class="pre">unicode</span></code></a></td> <td><code class="docutils literal notranslate"><span class="pre">TEXT</span></code></td> </tr> <tr class="row-even"><td><a class="reference internal" href="functions.html#buffer" title="buffer"><code class="xref py py-class docutils literal notranslate"><span class="pre">buffer</span></code></a></td> <td><code class="docutils literal notranslate"><span class="pre">BLOB</span></code></td> </tr> </tbody> </table> <p>This is how SQLite types are converted to Python types by default:</p> <table border="1" class="docutils"> <colgroup> <col width="22%" /> <col width="78%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">SQLite type</th> <th class="head">Python type</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">NULL</span></code></td> <td><a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a></td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">INTEGER</span></code></td> <td><a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a> or <a class="reference internal" href="functions.html#long" title="long"><code class="xref py py-class docutils literal notranslate"><span class="pre">long</span></code></a>, depending on size</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">REAL</span></code></td> <td><a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a></td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">TEXT</span></code></td> <td>depends on <a class="reference internal" href="#sqlite3.Connection.text_factory" title="sqlite3.Connection.text_factory"><code class="xref py py-attr docutils literal notranslate"><span class="pre">text_factory</span></code></a>, <a class="reference internal" href="functions.html#unicode" title="unicode"><code class="xref py py-class docutils literal notranslate"><span class="pre">unicode</span></code></a> by default</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">BLOB</span></code></td> <td><a class="reference internal" href="functions.html#buffer" title="buffer"><code class="xref py py-class docutils literal notranslate"><span class="pre">buffer</span></code></a></td> </tr> </tbody> </table> <p>The type system of the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module is extensible in two ways: you can store additional Python types in a SQLite database via object adaptation, and you can let the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module convert SQLite types to different Python types via converters.</p> </div> <div class="section" id="using-adapters-to-store-additional-python-types-in-sqlite-databases"> <h3>11.13.5.2. Using adapters to store additional Python types in SQLite databases<a class="headerlink" href="#using-adapters-to-store-additional-python-types-in-sqlite-databases" title="Permalink to this headline">¶</a></h3> <p>As described before, SQLite supports only a limited set of types natively. To use other Python types with SQLite, you must <strong>adapt</strong> them to one of the sqlite3 module’s supported types for SQLite: one of NoneType, int, long, float, str, unicode, buffer.</p> <p>There are two ways to enable the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module to adapt a custom Python type to one of the supported ones.</p> <div class="section" id="letting-your-object-adapt-itself"> <h4>11.13.5.2.1. Letting your object adapt itself<a class="headerlink" href="#letting-your-object-adapt-itself" title="Permalink to this headline">¶</a></h4> <p>This is a good approach if you write the class yourself. Let’s suppose you have a class like this:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Point</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span> <span class="o">=</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span> </pre></div> </div> <p>Now you want to store the point in a single SQLite column. First you’ll have to choose one of the supported types first to be used for representing the point. Let’s just use str and separate the coordinates using a semicolon. Then you need to give your class a method <code class="docutils literal notranslate"><span class="pre">__conform__(self,</span> <span class="pre">protocol)</span></code> which must return the converted value. The parameter <em>protocol</em> will be <code class="xref py py-class docutils literal notranslate"><span class="pre">PrepareProtocol</span></code>.</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">class</span> <span class="nc">Point</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span> <span class="o">=</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span> <span class="k">def</span> <span class="nf">__conform__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">protocol</span><span class="p">):</span> <span class="k">if</span> <span class="n">protocol</span> <span class="ow">is</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">PrepareProtocol</span><span class="p">:</span> <span class="k">return</span> <span class="s2">"</span><span class="si">%f</span><span class="s2">;</span><span class="si">%f</span><span class="s2">"</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span><span class="p">)</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">p</span> <span class="o">=</span> <span class="n">Point</span><span class="p">(</span><span class="mf">4.0</span><span class="p">,</span> <span class="o">-</span><span class="mf">3.2</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="n">p</span><span class="p">,))</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> </pre></div> </div> </div> <div class="section" id="registering-an-adapter-callable"> <h4>11.13.5.2.2. Registering an adapter callable<a class="headerlink" href="#registering-an-adapter-callable" title="Permalink to this headline">¶</a></h4> <p>The other possibility is to create a function that converts the type to the string representation and register the function with <a class="reference internal" href="#sqlite3.register_adapter" title="sqlite3.register_adapter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">register_adapter()</span></code></a>.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">The type/class to adapt must be a <a class="reference internal" href="../glossary.html#term-new-style-class"><span class="xref std std-term">new-style class</span></a>, i. e. it must have <a class="reference internal" href="functions.html#object" title="object"><code class="xref py py-class docutils literal notranslate"><span class="pre">object</span></code></a> as one of its bases.</p> </div> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">class</span> <span class="nc">Point</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span> <span class="o">=</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span> <span class="k">def</span> <span class="nf">adapt_point</span><span class="p">(</span><span class="n">point</span><span class="p">):</span> <span class="k">return</span> <span class="s2">"</span><span class="si">%f</span><span class="s2">;</span><span class="si">%f</span><span class="s2">"</span> <span class="o">%</span> <span class="p">(</span><span class="n">point</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="n">point</span><span class="o">.</span><span class="n">y</span><span class="p">)</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">register_adapter</span><span class="p">(</span><span class="n">Point</span><span class="p">,</span> <span class="n">adapt_point</span><span class="p">)</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">p</span> <span class="o">=</span> <span class="n">Point</span><span class="p">(</span><span class="mf">4.0</span><span class="p">,</span> <span class="o">-</span><span class="mf">3.2</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="n">p</span><span class="p">,))</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> </pre></div> </div> <p>The <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module has two default adapters for Python’s built-in <a class="reference internal" href="datetime.html#datetime.date" title="datetime.date"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.date</span></code></a> and <a class="reference internal" href="datetime.html#datetime.datetime" title="datetime.datetime"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.datetime</span></code></a> types. Now let’s suppose we want to store <a class="reference internal" href="datetime.html#datetime.datetime" title="datetime.datetime"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.datetime</span></code></a> objects not in ISO representation, but as a Unix timestamp.</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="kn">import</span> <span class="nn">datetime</span><span class="o">,</span> <span class="nn">time</span> <span class="k">def</span> <span class="nf">adapt_datetime</span><span class="p">(</span><span class="n">ts</span><span class="p">):</span> <span class="k">return</span> <span class="n">time</span><span class="o">.</span><span class="n">mktime</span><span class="p">(</span><span class="n">ts</span><span class="o">.</span><span class="n">timetuple</span><span class="p">())</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">register_adapter</span><span class="p">(</span><span class="n">datetime</span><span class="o">.</span><span class="n">datetime</span><span class="p">,</span> <span class="n">adapt_datetime</span><span class="p">)</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">now</span> <span class="o">=</span> <span class="n">datetime</span><span class="o">.</span><span class="n">datetime</span><span class="o">.</span><span class="n">now</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select ?"</span><span class="p">,</span> <span class="p">(</span><span class="n">now</span><span class="p">,))</span> <span class="nb">print</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> </pre></div> </div> </div> </div> <div class="section" id="converting-sqlite-values-to-custom-python-types"> <h3>11.13.5.3. Converting SQLite values to custom Python types<a class="headerlink" href="#converting-sqlite-values-to-custom-python-types" title="Permalink to this headline">¶</a></h3> <p>Writing an adapter lets you send custom Python types to SQLite. But to make it really useful we need to make the Python to SQLite to Python roundtrip work.</p> <p>Enter converters.</p> <p>Let’s go back to the <code class="xref py py-class docutils literal notranslate"><span class="pre">Point</span></code> class. We stored the x and y coordinates separated via semicolons as strings in SQLite.</p> <p>First, we’ll define a converter function that accepts the string as a parameter and constructs a <code class="xref py py-class docutils literal notranslate"><span class="pre">Point</span></code> object from it.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Converter functions <strong>always</strong> get called with a string, no matter under which data type you sent the value to SQLite.</p> </div> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">convert_point</span><span class="p">(</span><span class="n">s</span><span class="p">):</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span> <span class="o">=</span> <span class="nb">map</span><span class="p">(</span><span class="nb">float</span><span class="p">,</span> <span class="n">s</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s2">";"</span><span class="p">))</span> <span class="k">return</span> <span class="n">Point</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">)</span> </pre></div> </div> <p>Now you need to make the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module know that what you select from the database is actually a point. There are two ways of doing this:</p> <ul class="simple"> <li>Implicitly via the declared type</li> <li>Explicitly via the column name</li> </ul> <p>Both ways are described in section <a class="reference internal" href="#sqlite3-module-contents"><span class="std std-ref">Module functions and constants</span></a>, in the entries for the constants <a class="reference internal" href="#sqlite3.PARSE_DECLTYPES" title="sqlite3.PARSE_DECLTYPES"><code class="xref py py-const docutils literal notranslate"><span class="pre">PARSE_DECLTYPES</span></code></a> and <a class="reference internal" href="#sqlite3.PARSE_COLNAMES" title="sqlite3.PARSE_COLNAMES"><code class="xref py py-const docutils literal notranslate"><span class="pre">PARSE_COLNAMES</span></code></a>.</p> <p>The following example illustrates both approaches.</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="k">class</span> <span class="nc">Point</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span> <span class="o">=</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span> <span class="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="s2">"(</span><span class="si">%f</span><span class="s2">;</span><span class="si">%f</span><span class="s2">)"</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span><span class="p">)</span> <span class="k">def</span> <span class="nf">adapt_point</span><span class="p">(</span><span class="n">point</span><span class="p">):</span> <span class="k">return</span> <span class="s2">"</span><span class="si">%f</span><span class="s2">;</span><span class="si">%f</span><span class="s2">"</span> <span class="o">%</span> <span class="p">(</span><span class="n">point</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="n">point</span><span class="o">.</span><span class="n">y</span><span class="p">)</span> <span class="k">def</span> <span class="nf">convert_point</span><span class="p">(</span><span class="n">s</span><span class="p">):</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span> <span class="o">=</span> <span class="nb">map</span><span class="p">(</span><span class="nb">float</span><span class="p">,</span> <span class="n">s</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s2">";"</span><span class="p">))</span> <span class="k">return</span> <span class="n">Point</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">)</span> <span class="c1"># Register the adapter</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">register_adapter</span><span class="p">(</span><span class="n">Point</span><span class="p">,</span> <span class="n">adapt_point</span><span class="p">)</span> <span class="c1"># Register the converter</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">register_converter</span><span class="p">(</span><span class="s2">"point"</span><span class="p">,</span> <span class="n">convert_point</span><span class="p">)</span> <span class="n">p</span> <span class="o">=</span> <span class="n">Point</span><span class="p">(</span><span class="mf">4.0</span><span class="p">,</span> <span class="o">-</span><span class="mf">3.2</span><span class="p">)</span> <span class="c1">#########################</span> <span class="c1"># 1) Using declared types</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">,</span> <span class="n">detect_types</span><span class="o">=</span><span class="n">sqlite3</span><span class="o">.</span><span class="n">PARSE_DECLTYPES</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table test(p point)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into test(p) values (?)"</span><span class="p">,</span> <span class="p">(</span><span class="n">p</span><span class="p">,))</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select p from test"</span><span class="p">)</span> <span class="nb">print</span> <span class="s2">"with declared types:"</span><span class="p">,</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> <span class="n">cur</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> <span class="n">con</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> <span class="c1">#######################</span> <span class="c1"># 1) Using column names</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">,</span> <span class="n">detect_types</span><span class="o">=</span><span class="n">sqlite3</span><span class="o">.</span><span class="n">PARSE_COLNAMES</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table test(p)"</span><span class="p">)</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into test(p) values (?)"</span><span class="p">,</span> <span class="p">(</span><span class="n">p</span><span class="p">,))</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'select p as "p [point]" from test'</span><span class="p">)</span> <span class="nb">print</span> <span class="s2">"with column names:"</span><span class="p">,</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span> <span class="n">cur</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> <span class="n">con</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> </pre></div> </div> </div> <div class="section" id="default-adapters-and-converters"> <h3>11.13.5.4. Default adapters and converters<a class="headerlink" href="#default-adapters-and-converters" title="Permalink to this headline">¶</a></h3> <p>There are default adapters for the date and datetime types in the datetime module. They will be sent as ISO dates/ISO timestamps to SQLite.</p> <p>The default converters are registered under the name “date” for <a class="reference internal" href="datetime.html#datetime.date" title="datetime.date"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.date</span></code></a> and under the name “timestamp” for <a class="reference internal" href="datetime.html#datetime.datetime" title="datetime.datetime"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.datetime</span></code></a>.</p> <p>This way, you can use date/timestamps from Python without any additional fiddling in most cases. The format of the adapters is also compatible with the experimental SQLite date/time functions.</p> <p>The following example demonstrates this.</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="kn">import</span> <span class="nn">datetime</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">,</span> <span class="n">detect_types</span><span class="o">=</span><span class="n">sqlite3</span><span class="o">.</span><span class="n">PARSE_DECLTYPES</span><span class="o">|</span><span class="n">sqlite3</span><span class="o">.</span><span class="n">PARSE_COLNAMES</span><span class="p">)</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table test(d date, ts timestamp)"</span><span class="p">)</span> <span class="n">today</span> <span class="o">=</span> <span class="n">datetime</span><span class="o">.</span><span class="n">date</span><span class="o">.</span><span class="n">today</span><span class="p">()</span> <span class="n">now</span> <span class="o">=</span> <span class="n">datetime</span><span class="o">.</span><span class="n">datetime</span><span class="o">.</span><span class="n">now</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into test(d, ts) values (?, ?)"</span><span class="p">,</span> <span class="p">(</span><span class="n">today</span><span class="p">,</span> <span class="n">now</span><span class="p">))</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select d, ts from test"</span><span class="p">)</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="nb">print</span> <span class="n">today</span><span class="p">,</span> <span class="s2">"=>"</span><span class="p">,</span> <span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span> <span class="nb">print</span> <span class="n">now</span><span class="p">,</span> <span class="s2">"=>"</span><span class="p">,</span> <span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'select current_date as "d [date]", current_timestamp as "ts [timestamp]"'</span><span class="p">)</span> <span class="n">row</span> <span class="o">=</span> <span class="n">cur</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span> <span class="nb">print</span> <span class="s2">"current_date"</span><span class="p">,</span> <span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span> <span class="nb">print</span> <span class="s2">"current_timestamp"</span><span class="p">,</span> <span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="nb">type</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span> </pre></div> </div> <p>If a timestamp stored in SQLite has a fractional part longer than 6 numbers, its value will be truncated to microsecond precision by the timestamp converter.</p> </div> </div> <div class="section" id="controlling-transactions"> <span id="sqlite3-controlling-transactions"></span><h2>11.13.6. Controlling Transactions<a class="headerlink" href="#controlling-transactions" title="Permalink to this headline">¶</a></h2> <p>By default, the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module opens transactions implicitly before a Data Modification Language (DML) statement (i.e. <code class="docutils literal notranslate"><span class="pre">INSERT</span></code>/<code class="docutils literal notranslate"><span class="pre">UPDATE</span></code>/<code class="docutils literal notranslate"><span class="pre">DELETE</span></code>/<code class="docutils literal notranslate"><span class="pre">REPLACE</span></code>), and commits transactions implicitly before a non-DML, non-query statement (i. e. anything other than <code class="docutils literal notranslate"><span class="pre">SELECT</span></code> or the aforementioned).</p> <p>So if you are within a transaction and issue a command like <code class="docutils literal notranslate"><span class="pre">CREATE</span> <span class="pre">TABLE</span> <span class="pre">...</span></code>, <code class="docutils literal notranslate"><span class="pre">VACUUM</span></code>, <code class="docutils literal notranslate"><span class="pre">PRAGMA</span></code>, the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module will commit implicitly before executing that command. There are two reasons for doing that. The first is that some of these commands don’t work within transactions. The other reason is that sqlite3 needs to keep track of the transaction state (if a transaction is active or not).</p> <p>You can control which kind of <code class="docutils literal notranslate"><span class="pre">BEGIN</span></code> statements sqlite3 implicitly executes (or none at all) via the <em>isolation_level</em> parameter to the <a class="reference internal" href="#sqlite3.connect" title="sqlite3.connect"><code class="xref py py-func docutils literal notranslate"><span class="pre">connect()</span></code></a> call, or via the <code class="xref py py-attr docutils literal notranslate"><span class="pre">isolation_level</span></code> property of connections.</p> <p>If you want <strong>autocommit mode</strong>, then set <code class="xref py py-attr docutils literal notranslate"><span class="pre">isolation_level</span></code> to <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p> <p>Otherwise leave it at its default, which will result in a plain “BEGIN” statement, or set it to one of SQLite’s supported isolation levels: “DEFERRED”, “IMMEDIATE” or “EXCLUSIVE”.</p> </div> <div class="section" id="using-sqlite3-efficiently"> <h2>11.13.7. Using <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> efficiently<a class="headerlink" href="#using-sqlite3-efficiently" title="Permalink to this headline">¶</a></h2> <div class="section" id="using-shortcut-methods"> <h3>11.13.7.1. Using shortcut methods<a class="headerlink" href="#using-shortcut-methods" title="Permalink to this headline">¶</a></h3> <p>Using the nonstandard <code class="xref py py-meth docutils literal notranslate"><span class="pre">execute()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">executemany()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">executescript()</span></code> methods of the <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> object, your code can be written more concisely because you don’t have to create the (often superfluous) <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> objects explicitly. Instead, the <a class="reference internal" href="#sqlite3.Cursor" title="sqlite3.Cursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> objects are created implicitly and these shortcut methods return the cursor objects. This way, you can execute a <code class="docutils literal notranslate"><span class="pre">SELECT</span></code> statement and iterate over it directly using only a single call on the <a class="reference internal" href="multiprocessing.html#Connection" title="Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a> object.</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">persons</span> <span class="o">=</span> <span class="p">[</span> <span class="p">(</span><span class="s2">"Hugo"</span><span class="p">,</span> <span class="s2">"Boss"</span><span class="p">),</span> <span class="p">(</span><span class="s2">"Calvin"</span><span class="p">,</span> <span class="s2">"Klein"</span><span class="p">)</span> <span class="p">]</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="c1"># Create the table</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table person(firstname, lastname)"</span><span class="p">)</span> <span class="c1"># Fill the table</span> <span class="n">con</span><span class="o">.</span><span class="n">executemany</span><span class="p">(</span><span class="s2">"insert into person(firstname, lastname) values (?, ?)"</span><span class="p">,</span> <span class="n">persons</span><span class="p">)</span> <span class="c1"># Print the table contents</span> <span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select firstname, lastname from person"</span><span class="p">):</span> <span class="nb">print</span> <span class="n">row</span> <span class="nb">print</span> <span class="s2">"I just deleted"</span><span class="p">,</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"delete from person"</span><span class="p">)</span><span class="o">.</span><span class="n">rowcount</span><span class="p">,</span> <span class="s2">"rows"</span> </pre></div> </div> </div> <div class="section" id="accessing-columns-by-name-instead-of-by-index"> <h3>11.13.7.2. Accessing columns by name instead of by index<a class="headerlink" href="#accessing-columns-by-name-instead-of-by-index" title="Permalink to this headline">¶</a></h3> <p>One useful feature of the <a class="reference internal" href="#module-sqlite3" title="sqlite3: A DB-API 2.0 implementation using SQLite 3.x."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code></a> module is the built-in <a class="reference internal" href="#sqlite3.Row" title="sqlite3.Row"><code class="xref py py-class docutils literal notranslate"><span class="pre">sqlite3.Row</span></code></a> class designed to be used as a row factory.</p> <p>Rows wrapped with this class can be accessed both by index (like tuples) and case-insensitively by name:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">row_factory</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">Row</span> <span class="n">cur</span> <span class="o">=</span> <span class="n">con</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span> <span class="n">cur</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"select 'John' as name, 42 as age"</span><span class="p">)</span> <span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">cur</span><span class="p">:</span> <span class="k">assert</span> <span class="n">row</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">==</span> <span class="n">row</span><span class="p">[</span><span class="s2">"name"</span><span class="p">]</span> <span class="k">assert</span> <span class="n">row</span><span class="p">[</span><span class="s2">"name"</span><span class="p">]</span> <span class="o">==</span> <span class="n">row</span><span class="p">[</span><span class="s2">"nAmE"</span><span class="p">]</span> <span class="k">assert</span> <span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">==</span> <span class="n">row</span><span class="p">[</span><span class="s2">"age"</span><span class="p">]</span> <span class="k">assert</span> <span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">==</span> <span class="n">row</span><span class="p">[</span><span class="s2">"AgE"</span><span class="p">]</span> </pre></div> </div> </div> <div class="section" id="using-the-connection-as-a-context-manager"> <h3>11.13.7.3. Using the connection as a context manager<a class="headerlink" href="#using-the-connection-as-a-context-manager" title="Permalink to this headline">¶</a></h3> <div class="versionadded"> <p><span class="versionmodified">New in version 2.6.</span></p> </div> <p>Connection objects can be used as context managers that automatically commit or rollback transactions. In the event of an exception, the transaction is rolled back; otherwise, the transaction is committed:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">sqlite3</span> <span class="n">con</span> <span class="o">=</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="s2">":memory:"</span><span class="p">)</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create table person (id integer primary key, firstname varchar unique)"</span><span class="p">)</span> <span class="c1"># Successful, con.commit() is called automatically afterwards</span> <span class="k">with</span> <span class="n">con</span><span class="p">:</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into person(firstname) values (?)"</span><span class="p">,</span> <span class="p">(</span><span class="s2">"Joe"</span><span class="p">,))</span> <span class="c1"># con.rollback() is called after the with block finishes with an exception, the</span> <span class="c1"># exception is still raised and must be caught</span> <span class="k">try</span><span class="p">:</span> <span class="k">with</span> <span class="n">con</span><span class="p">:</span> <span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"insert into person(firstname) values (?)"</span><span class="p">,</span> <span class="p">(</span><span class="s2">"Joe"</span><span class="p">,))</span> <span class="k">except</span> <span class="n">sqlite3</span><span class="o">.</span><span class="n">IntegrityError</span><span class="p">:</span> <span class="nb">print</span> <span class="s2">"couldn't add Joe twice"</span> </pre></div> </div> </div> </div> <div class="section" id="common-issues"> <h2>11.13.8. Common issues<a class="headerlink" href="#common-issues" title="Permalink to this headline">¶</a></h2> <div class="section" id="multithreading"> <h3>11.13.8.1. Multithreading<a class="headerlink" href="#multithreading" title="Permalink to this headline">¶</a></h3> <p>Older SQLite versions had issues with sharing connections between threads. That’s why the Python module disallows sharing connections and cursors between threads. If you still try to do so, you will get an exception at runtime.</p> <p>The only exception is calling the <a class="reference internal" href="#sqlite3.Connection.interrupt" title="sqlite3.Connection.interrupt"><code class="xref py py-meth docutils literal notranslate"><span class="pre">interrupt()</span></code></a> method, which only makes sense to call from a different thread.</p> <p class="rubric">Footnotes</p> <table class="docutils footnote" frame="void" id="f1" rules="none"> <colgroup><col class="label" /><col /></colgroup> <tbody valign="top"> <tr><td class="label">[1]</td><td><em>(<a class="fn-backref" href="#id1">1</a>, <a class="fn-backref" href="#id2">2</a>)</em> The sqlite3 module is not built with loadable extension support by default, because some platforms (notably Mac OS X) have SQLite libraries which are compiled without this feature. To get loadable extension support, you must modify setup.py and remove the line that sets SQLITE_OMIT_LOAD_EXTENSION.</td></tr> </tbody> </table> </div> </div> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table of Contents</a></h3> <ul> <li><a class="reference internal" href="#">11.13. <code class="docutils literal notranslate"><span class="pre">sqlite3</span></code> — DB-API 2.0 interface for SQLite databases</a><ul> <li><a class="reference internal" href="#module-functions-and-constants">11.13.1. Module functions and constants</a></li> <li><a class="reference internal" href="#connection-objects">11.13.2. Connection Objects</a></li> <li><a class="reference internal" href="#cursor-objects">11.13.3. Cursor Objects</a></li> <li><a class="reference internal" href="#row-objects">11.13.4. Row Objects</a></li> <li><a class="reference internal" href="#sqlite-and-python-types">11.13.5. SQLite and Python types</a><ul> <li><a class="reference internal" href="#introduction">11.13.5.1. Introduction</a></li> <li><a class="reference internal" href="#using-adapters-to-store-additional-python-types-in-sqlite-databases">11.13.5.2. Using adapters to store additional Python types in SQLite databases</a><ul> <li><a class="reference internal" href="#letting-your-object-adapt-itself">11.13.5.2.1. Letting your object adapt itself</a></li> <li><a class="reference internal" href="#registering-an-adapter-callable">11.13.5.2.2. Registering an adapter callable</a></li> </ul> </li> <li><a class="reference internal" href="#converting-sqlite-values-to-custom-python-types">11.13.5.3. Converting SQLite values to custom Python types</a></li> <li><a class="reference internal" href="#default-adapters-and-converters">11.13.5.4. Default adapters and converters</a></li> </ul> </li> <li><a class="reference internal" href="#controlling-transactions">11.13.6. Controlling Transactions</a></li> <li><a class="reference internal" href="#using-sqlite3-efficiently">11.13.7. Using <code class="docutils literal notranslate"><span class="pre">sqlite3</span></code> efficiently</a><ul> <li><a class="reference internal" href="#using-shortcut-methods">11.13.7.1. Using shortcut methods</a></li> <li><a class="reference internal" href="#accessing-columns-by-name-instead-of-by-index">11.13.7.2. Accessing columns by name instead of by index</a></li> <li><a class="reference internal" href="#using-the-connection-as-a-context-manager">11.13.7.3. Using the connection as a context manager</a></li> </ul> </li> <li><a class="reference internal" href="#common-issues">11.13.8. Common issues</a><ul> <li><a class="reference internal" href="#multithreading">11.13.8.1. Multithreading</a></li> </ul> </li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="dumbdbm.html" title="previous chapter">11.12. <code class="docutils literal notranslate"><span class="pre">dumbdbm</span></code> — Portable DBM implementation</a></p> <h4>Next topic</h4> <p class="topless"><a href="archiving.html" title="next chapter">12. 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