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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code> — Interfaces to Unix “databases”</a><ul>
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<li><a class="reference internal" href="#module-dbm.sqlite3"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.sqlite3</span></code> — SQLite backend for dbm</a></li>
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<li><a class="reference internal" href="#module-dbm.gnu"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code> — GNU database manager</a></li>
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<li><a class="reference internal" href="#module-dbm.ndbm"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code> — New Database Manager</a></li>
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<li><a class="reference internal" href="#module-dbm.dumb"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code> — Portable DBM implementation</a></li>
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<section id="module-dbm">
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<span id="dbm-interfaces-to-unix-databases"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code> — Interfaces to Unix “databases”<a class="headerlink" href="#module-dbm" title="Link to this heading">¶</a></h1>
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<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/dbm/__init__.py">Lib/dbm/__init__.py</a></p>
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<hr class="docutils" />
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<p><a class="reference internal" href="#module-dbm" title="dbm: Interfaces to various Unix "database" formats."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code></a> is a generic interface to variants of the DBM database:</p>
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<ul class="simple">
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<li><p><a class="reference internal" href="#module-dbm.sqlite3" title="dbm.sqlite3: SQLite backend for dbm (All)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.sqlite3</span></code></a></p></li>
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<li><p><a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a></p></li>
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<li><p><a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a></p></li>
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</ul>
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<p>If none of these modules are installed, the
|
||
slow-but-simple implementation in module <a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a> will be used. There
|
||
is a <a class="reference external" href="https://www.jcea.es/programacion/pybsddb.htm">third party interface</a> to
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the Oracle Berkeley DB.</p>
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<dl class="py exception">
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<dt class="sig sig-object py" id="dbm.error">
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<em class="property"><span class="k"><span class="pre">exception</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">dbm.</span></span><span class="sig-name descname"><span class="pre">error</span></span><a class="headerlink" href="#dbm.error" title="Link to this definition">¶</a></dt>
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<dd><p>A tuple containing the exceptions that can be raised by each of the supported
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modules, with a unique exception also named <a class="reference internal" href="#dbm.error" title="dbm.error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">dbm.error</span></code></a> as the first
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item — the latter is used when <a class="reference internal" href="#dbm.error" title="dbm.error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">dbm.error</span></code></a> is raised.</p>
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</dd></dl>
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<dl class="py function">
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<dt class="sig sig-object py" id="dbm.whichdb">
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<span class="sig-prename descclassname"><span class="pre">dbm.</span></span><span class="sig-name descname"><span class="pre">whichdb</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.whichdb" title="Link to this definition">¶</a></dt>
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<dd><p>This function attempts to guess which of the several simple database modules
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available — <a class="reference internal" href="#module-dbm.sqlite3" title="dbm.sqlite3: SQLite backend for dbm (All)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.sqlite3</span></code></a>, <a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a>, <a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a>,
|
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or <a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a> — should be used to open a given file.</p>
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<p>Return one of the following values:</p>
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<ul class="simple">
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<li><p><code class="docutils literal notranslate"><span class="pre">None</span></code> if the file can’t be opened because it’s unreadable or doesn’t exist</p></li>
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<li><p>the empty string (<code class="docutils literal notranslate"><span class="pre">''</span></code>) if the file’s format can’t be guessed</p></li>
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<li><p>a string containing the required module name, such as <code class="docutils literal notranslate"><span class="pre">'dbm.ndbm'</span></code> or <code class="docutils literal notranslate"><span class="pre">'dbm.gnu'</span></code></p></li>
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</ul>
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<div class="versionchanged">
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<p><span class="versionmodified changed">Changed in version 3.11: </span><em>filename</em> accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
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</div>
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</dd></dl>
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<dl class="py function">
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<dt class="sig sig-object py" id="dbm.open">
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<span class="sig-prename descclassname"><span class="pre">dbm.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">file</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flag</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0o666</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.open" title="Link to this definition">¶</a></dt>
|
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<dd><p>Open a database and return the corresponding database object.</p>
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<dl class="field-list simple">
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<dt class="field-odd">Parameters<span class="colon">:</span></dt>
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<dd class="field-odd"><ul class="simple">
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<li><p><strong>file</strong> (<a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>) – <p>The database file to open.</p>
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<p>If the database file already exists, the <a class="reference internal" href="#dbm.whichdb" title="dbm.whichdb"><code class="xref py py-func docutils literal notranslate"><span class="pre">whichdb()</span></code></a> function is used to
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determine its type and the appropriate module is used; if it does not exist,
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the first submodule listed above that can be imported is used.</p>
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</p></li>
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<li><p><strong>flag</strong> (<a class="reference internal" href="stdtypes.html#str" title="str"><em>str</em></a>) – <ul>
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<li><p><code class="docutils literal notranslate"><span class="pre">'r'</span></code> (default): Open existing database for reading only.</p></li>
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<li><p><code class="docutils literal notranslate"><span class="pre">'w'</span></code>: Open existing database for reading and writing.</p></li>
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<li><p><code class="docutils literal notranslate"><span class="pre">'c'</span></code>: Open database for reading and writing, creating it if it doesn’t exist.</p></li>
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<li><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code>: Always create a new, empty database, open for reading and writing.</p></li>
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</ul>
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</p></li>
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<li><p><strong>mode</strong> (<a class="reference internal" href="functions.html#int" title="int"><em>int</em></a>) – The Unix file access mode of the file (default: octal <code class="docutils literal notranslate"><span class="pre">0o666</span></code>),
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used only when the database has to be created.</p></li>
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</ul>
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</dd>
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</dl>
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<div class="versionchanged">
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<p><span class="versionmodified changed">Changed in version 3.11: </span><em>file</em> accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
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</div>
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</dd></dl>
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<p>The object returned by <a class="reference internal" href="#dbm.open" title="dbm.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> supports the same basic functionality as a
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<a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate"><span class="pre">dict</span></code></a>; keys and their corresponding values can be stored, retrieved, and
|
||
deleted, and the <a class="reference internal" href="../reference/expressions.html#in"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">in</span></code></a> operator and the <code class="xref py py-meth docutils literal notranslate"><span class="pre">keys()</span></code> method are
|
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available, as well as <code class="xref py py-meth docutils literal notranslate"><span class="pre">get()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">setdefault()</span></code> methods.</p>
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<p>Key and values are always stored as <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>. This means that when
|
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strings are used they are implicitly converted to the default encoding before
|
||
being stored.</p>
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<p>These objects also support being used in a <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> statement, which
|
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will automatically close them when done.</p>
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<div class="versionchanged">
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||
<p><span class="versionmodified changed">Changed in version 3.2: </span><code class="xref py py-meth docutils literal notranslate"><span class="pre">get()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">setdefault()</span></code> methods are now available for all
|
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<a class="reference internal" href="#module-dbm" title="dbm: Interfaces to various Unix "database" formats."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code></a> backends.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.4: </span>Added native support for the context management protocol to the objects
|
||
returned by <a class="reference internal" href="#dbm.open" title="dbm.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a>.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.8: </span>Deleting a key from a read-only database raises a database module specific exception
|
||
instead of <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a>.</p>
|
||
</div>
|
||
<p>The following example records some hostnames and a corresponding title, and
|
||
then prints out the contents of the database:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">dbm</span>
|
||
|
||
<span class="c1"># Open database, creating it if necessary.</span>
|
||
<span class="k">with</span> <span class="n">dbm</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s1">'cache'</span><span class="p">,</span> <span class="s1">'c'</span><span class="p">)</span> <span class="k">as</span> <span class="n">db</span><span class="p">:</span>
|
||
|
||
<span class="c1"># Record some values</span>
|
||
<span class="n">db</span><span class="p">[</span><span class="sa">b</span><span class="s1">'hello'</span><span class="p">]</span> <span class="o">=</span> <span class="sa">b</span><span class="s1">'there'</span>
|
||
<span class="n">db</span><span class="p">[</span><span class="s1">'www.python.org'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'Python Website'</span>
|
||
<span class="n">db</span><span class="p">[</span><span class="s1">'www.cnn.com'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'Cable News Network'</span>
|
||
|
||
<span class="c1"># Note that the keys are considered bytes now.</span>
|
||
<span class="k">assert</span> <span class="n">db</span><span class="p">[</span><span class="sa">b</span><span class="s1">'www.python.org'</span><span class="p">]</span> <span class="o">==</span> <span class="sa">b</span><span class="s1">'Python Website'</span>
|
||
<span class="c1"># Notice how the value is now in bytes.</span>
|
||
<span class="k">assert</span> <span class="n">db</span><span class="p">[</span><span class="s1">'www.cnn.com'</span><span class="p">]</span> <span class="o">==</span> <span class="sa">b</span><span class="s1">'Cable News Network'</span>
|
||
|
||
<span class="c1"># Often-used methods of the dict interface work too.</span>
|
||
<span class="nb">print</span><span class="p">(</span><span class="n">db</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">'python.org'</span><span class="p">,</span> <span class="sa">b</span><span class="s1">'not present'</span><span class="p">))</span>
|
||
|
||
<span class="c1"># Storing a non-string key or value will raise an exception (most</span>
|
||
<span class="c1"># likely a TypeError).</span>
|
||
<span class="n">db</span><span class="p">[</span><span class="s1">'www.yahoo.com'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">4</span>
|
||
|
||
<span class="c1"># db is automatically closed when leaving the with statement.</span>
|
||
</pre></div>
|
||
</div>
|
||
<div class="admonition seealso">
|
||
<p class="admonition-title">See also</p>
|
||
<dl class="simple">
|
||
<dt>Module <a class="reference internal" href="shelve.html#module-shelve" title="shelve: Python object persistence."><code class="xref py py-mod docutils literal notranslate"><span class="pre">shelve</span></code></a></dt><dd><p>Persistence module which stores non-string data.</p>
|
||
</dd>
|
||
</dl>
|
||
</div>
|
||
<p>The individual submodules are described in the following sections.</p>
|
||
<section id="module-dbm.sqlite3">
|
||
<span id="dbm-sqlite3-sqlite-backend-for-dbm"></span><h2><a class="reference internal" href="#module-dbm.sqlite3" title="dbm.sqlite3: SQLite backend for dbm (All)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.sqlite3</span></code></a> — SQLite backend for dbm<a class="headerlink" href="#module-dbm.sqlite3" title="Link to this heading">¶</a></h2>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 3.13.</span></p>
|
||
</div>
|
||
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/dbm/sqlite3.py">Lib/dbm/sqlite3.py</a></p>
|
||
<hr class="docutils" />
|
||
<p>This module uses the standard library <a class="reference internal" href="sqlite3.html#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 provide an
|
||
SQLite backend for the <a class="reference internal" href="#module-dbm" title="dbm: Interfaces to various Unix "database" formats."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code></a> module.
|
||
The files created by <a class="reference internal" href="#module-dbm.sqlite3" title="dbm.sqlite3: SQLite backend for dbm (All)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.sqlite3</span></code></a> can thus be opened by <a class="reference internal" href="sqlite3.html#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>,
|
||
or any other SQLite browser, including the SQLite CLI.</p>
|
||
<div class="availability docutils container">
|
||
<p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>
|
||
<p>This module does not work or is not available on WebAssembly. See
|
||
<a class="reference internal" href="intro.html#wasm-availability"><span class="std std-ref">WebAssembly platforms</span></a> for more information.</p>
|
||
</div>
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="dbm.sqlite3.open">
|
||
<span class="sig-prename descclassname"><span class="pre">dbm.sqlite3.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">flag</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0o666</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.sqlite3.open" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Open an SQLite database.
|
||
The returned object behaves like a <a class="reference internal" href="../glossary.html#term-mapping"><span class="xref std std-term">mapping</span></a>,
|
||
implements a <code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code> method,
|
||
and supports a “closing” context manager via the <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> keyword.</p>
|
||
<dl class="field-list simple">
|
||
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
|
||
<dd class="field-odd"><ul class="simple">
|
||
<li><p><strong>filename</strong> (<a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>) – The path to the database to be opened.</p></li>
|
||
<li><p><strong>flag</strong> (<a class="reference internal" href="stdtypes.html#str" title="str"><em>str</em></a>) – <ul>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'r'</span></code> (default): Open existing database for reading only.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'w'</span></code>: Open existing database for reading and writing.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'c'</span></code>: Open database for reading and writing, creating it if it doesn’t exist.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code>: Always create a new, empty database, open for reading and writing.</p></li>
|
||
</ul>
|
||
</p></li>
|
||
<li><p><strong>mode</strong> – The Unix file access mode of the file (default: octal <code class="docutils literal notranslate"><span class="pre">0o666</span></code>),
|
||
used only when the database has to be created.</p></li>
|
||
</ul>
|
||
</dd>
|
||
</dl>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="module-dbm.gnu">
|
||
<span id="dbm-gnu-gnu-database-manager"></span><h2><a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a> — GNU database manager<a class="headerlink" href="#module-dbm.gnu" title="Link to this heading">¶</a></h2>
|
||
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/dbm/gnu.py">Lib/dbm/gnu.py</a></p>
|
||
<hr class="docutils" />
|
||
<p>The <a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a> module provides an interface to the <abbr title="GNU dbm">GDBM</abbr>
|
||
library, similar to the <a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a> module, but with additional
|
||
functionality like crash tolerance.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>The file formats created by <a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a> and <a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a> are incompatible
|
||
and can not be used interchangeably.</p>
|
||
</div>
|
||
<div class="availability docutils container">
|
||
<p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not Android, not iOS, not WASI.</p>
|
||
<p>This module is not supported on <a class="reference internal" href="intro.html#mobile-availability"><span class="std std-ref">mobile platforms</span></a>
|
||
or <a class="reference internal" href="intro.html#wasm-availability"><span class="std std-ref">WebAssembly platforms</span></a>.</p>
|
||
</div>
|
||
<dl class="py exception">
|
||
<dt class="sig sig-object py" id="dbm.gnu.error">
|
||
<em class="property"><span class="k"><span class="pre">exception</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">dbm.gnu.</span></span><span class="sig-name descname"><span class="pre">error</span></span><a class="headerlink" href="#dbm.gnu.error" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Raised on <a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a>-specific errors, such as I/O errors. <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> is
|
||
raised for general mapping errors like specifying an incorrect key.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="dbm.gnu.open">
|
||
<span class="sig-prename descclassname"><span class="pre">dbm.gnu.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flag</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0o666</span></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.open" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Open a GDBM database and return a <code class="xref py py-class docutils literal notranslate"><span class="pre">gdbm</span></code> object.</p>
|
||
<dl class="field-list simple">
|
||
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
|
||
<dd class="field-odd"><ul class="simple">
|
||
<li><p><strong>filename</strong> (<a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>) – The database file to open.</p></li>
|
||
<li><p><strong>flag</strong> (<a class="reference internal" href="stdtypes.html#str" title="str"><em>str</em></a>) – <ul>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'r'</span></code> (default): Open existing database for reading only.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'w'</span></code>: Open existing database for reading and writing.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'c'</span></code>: Open database for reading and writing, creating it if it doesn’t exist.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code>: Always create a new, empty database, open for reading and writing.</p></li>
|
||
</ul>
|
||
<p>The following additional characters may be appended
|
||
to control how the database is opened:</p>
|
||
<ul>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'f'</span></code>: Open the database in fast mode.
|
||
Writes to the database will not be synchronized.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'s'</span></code>: Synchronized mode.
|
||
Changes to the database will be written immediately to the file.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'u'</span></code>: Do not lock database.</p></li>
|
||
</ul>
|
||
<p>Not all flags are valid for all versions of GDBM.
|
||
See the <a class="reference internal" href="#dbm.gnu.open_flags" title="dbm.gnu.open_flags"><code class="xref py py-data docutils literal notranslate"><span class="pre">open_flags</span></code></a> member for a list of supported flag characters.</p>
|
||
</p></li>
|
||
<li><p><strong>mode</strong> (<a class="reference internal" href="functions.html#int" title="int"><em>int</em></a>) – The Unix file access mode of the file (default: octal <code class="docutils literal notranslate"><span class="pre">0o666</span></code>),
|
||
used only when the database has to be created.</p></li>
|
||
</ul>
|
||
</dd>
|
||
<dt class="field-even">Raises<span class="colon">:</span></dt>
|
||
<dd class="field-even"><p><a class="reference internal" href="#dbm.gnu.error" title="dbm.gnu.error"><strong>error</strong></a> – If an invalid <em>flag</em> argument is passed.</p>
|
||
</dd>
|
||
</dl>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.11: </span><em>filename</em> accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
|
||
</div>
|
||
<dl class="py data">
|
||
<dt class="sig sig-object py" id="dbm.gnu.open_flags">
|
||
<span class="sig-prename descclassname"><span class="pre">dbm.gnu.</span></span><span class="sig-name descname"><span class="pre">open_flags</span></span><a class="headerlink" href="#dbm.gnu.open_flags" title="Link to this definition">¶</a></dt>
|
||
<dd><p>A string of characters the <em>flag</em> parameter of <a class="reference internal" href="#dbm.gnu.open" title="dbm.gnu.open"><code class="xref py py-meth docutils literal notranslate"><span class="pre">open()</span></code></a> supports.</p>
|
||
</dd></dl>
|
||
|
||
<p><code class="xref py py-class docutils literal notranslate"><span class="pre">gdbm</span></code> objects behave similar to <a class="reference internal" href="../glossary.html#term-mapping"><span class="xref std std-term">mappings</span></a>,
|
||
but <code class="xref py py-meth docutils literal notranslate"><span class="pre">items()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">values()</span></code> methods are not supported.
|
||
The following methods are also provided:</p>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.gnu.gdbm.firstkey">
|
||
<span class="sig-prename descclassname"><span class="pre">gdbm.</span></span><span class="sig-name descname"><span class="pre">firstkey</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.gdbm.firstkey" title="Link to this definition">¶</a></dt>
|
||
<dd><p>It’s possible to loop over every key in the database using this method and the
|
||
<a class="reference internal" href="#dbm.gnu.gdbm.nextkey" title="dbm.gnu.gdbm.nextkey"><code class="xref py py-meth docutils literal notranslate"><span class="pre">nextkey()</span></code></a> method. The traversal is ordered by GDBM’s internal
|
||
hash values, and won’t be sorted by the key values. This method returns
|
||
the starting key.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.gnu.gdbm.nextkey">
|
||
<span class="sig-prename descclassname"><span class="pre">gdbm.</span></span><span class="sig-name descname"><span class="pre">nextkey</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">key</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.gdbm.nextkey" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Returns the key that follows <em>key</em> in the traversal. The following code prints
|
||
every key in the database <code class="docutils literal notranslate"><span class="pre">db</span></code>, without having to create a list in memory that
|
||
contains them all:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">k</span> <span class="o">=</span> <span class="n">db</span><span class="o">.</span><span class="n">firstkey</span><span class="p">()</span>
|
||
<span class="k">while</span> <span class="n">k</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
|
||
<span class="nb">print</span><span class="p">(</span><span class="n">k</span><span class="p">)</span>
|
||
<span class="n">k</span> <span class="o">=</span> <span class="n">db</span><span class="o">.</span><span class="n">nextkey</span><span class="p">(</span><span class="n">k</span><span class="p">)</span>
|
||
</pre></div>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.gnu.gdbm.reorganize">
|
||
<span class="sig-prename descclassname"><span class="pre">gdbm.</span></span><span class="sig-name descname"><span class="pre">reorganize</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.gdbm.reorganize" title="Link to this definition">¶</a></dt>
|
||
<dd><p>If you have carried out a lot of deletions and would like to shrink the space
|
||
used by the GDBM file, this routine will reorganize the database. <code class="xref py py-class docutils literal notranslate"><span class="pre">gdbm</span></code>
|
||
objects will not shorten the length of a database file except by using this
|
||
reorganization; otherwise, deleted file space will be kept and reused as new
|
||
(key, value) pairs are added.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.gnu.gdbm.sync">
|
||
<span class="sig-prename descclassname"><span class="pre">gdbm.</span></span><span class="sig-name descname"><span class="pre">sync</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.gdbm.sync" title="Link to this definition">¶</a></dt>
|
||
<dd><p>When the database has been opened in fast mode, this method forces any
|
||
unwritten data to be written to the disk.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.gnu.gdbm.close">
|
||
<span class="sig-prename descclassname"><span class="pre">gdbm.</span></span><span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.gdbm.close" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Close the GDBM database.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.gnu.gdbm.clear">
|
||
<span class="sig-prename descclassname"><span class="pre">gdbm.</span></span><span class="sig-name descname"><span class="pre">clear</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.gnu.gdbm.clear" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Remove all items from the GDBM database.</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 3.13.</span></p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="module-dbm.ndbm">
|
||
<span id="dbm-ndbm-new-database-manager"></span><h2><a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a> — New Database Manager<a class="headerlink" href="#module-dbm.ndbm" title="Link to this heading">¶</a></h2>
|
||
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/dbm/ndbm.py">Lib/dbm/ndbm.py</a></p>
|
||
<hr class="docutils" />
|
||
<p>The <a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a> module provides an interface to the
|
||
<abbr title="New Database Manager">NDBM</abbr> library.
|
||
This module can be used with the “classic” NDBM interface or the
|
||
<abbr title="GNU dbm">GDBM</abbr> compatibility interface.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>The file formats created by <a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a> and <a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a> are incompatible
|
||
and can not be used interchangeably.</p>
|
||
</div>
|
||
<div class="admonition warning">
|
||
<p class="admonition-title">Warning</p>
|
||
<p>The NDBM library shipped as part of macOS has an undocumented limitation on the
|
||
size of values, which can result in corrupted database files
|
||
when storing values larger than this limit. Reading such corrupted files can
|
||
result in a hard crash (segmentation fault).</p>
|
||
</div>
|
||
<div class="availability docutils container">
|
||
<p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not Android, not iOS, not WASI.</p>
|
||
<p>This module is not supported on <a class="reference internal" href="intro.html#mobile-availability"><span class="std std-ref">mobile platforms</span></a>
|
||
or <a class="reference internal" href="intro.html#wasm-availability"><span class="std std-ref">WebAssembly platforms</span></a>.</p>
|
||
</div>
|
||
<dl class="py exception">
|
||
<dt class="sig sig-object py" id="dbm.ndbm.error">
|
||
<em class="property"><span class="k"><span class="pre">exception</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">dbm.ndbm.</span></span><span class="sig-name descname"><span class="pre">error</span></span><a class="headerlink" href="#dbm.ndbm.error" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Raised on <a class="reference internal" href="#module-dbm.ndbm" title="dbm.ndbm: The New Database Manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code></a>-specific errors, such as I/O errors. <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> is raised
|
||
for general mapping errors like specifying an incorrect key.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py data">
|
||
<dt class="sig sig-object py" id="dbm.ndbm.library">
|
||
<span class="sig-prename descclassname"><span class="pre">dbm.ndbm.</span></span><span class="sig-name descname"><span class="pre">library</span></span><a class="headerlink" href="#dbm.ndbm.library" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Name of the NDBM implementation library used.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="dbm.ndbm.open">
|
||
<span class="sig-prename descclassname"><span class="pre">dbm.ndbm.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flag</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0o666</span></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.ndbm.open" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Open an NDBM database and return an <code class="xref py py-class docutils literal notranslate"><span class="pre">ndbm</span></code> object.</p>
|
||
<dl class="field-list simple">
|
||
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
|
||
<dd class="field-odd"><ul class="simple">
|
||
<li><p><strong>filename</strong> (<a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>) – The basename of the database file
|
||
(without the <code class="file docutils literal notranslate"><span class="pre">.dir</span></code> or <code class="file docutils literal notranslate"><span class="pre">.pag</span></code> extensions).</p></li>
|
||
<li><p><strong>flag</strong> (<a class="reference internal" href="stdtypes.html#str" title="str"><em>str</em></a>) – <ul>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'r'</span></code> (default): Open existing database for reading only.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'w'</span></code>: Open existing database for reading and writing.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'c'</span></code>: Open database for reading and writing, creating it if it doesn’t exist.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code>: Always create a new, empty database, open for reading and writing.</p></li>
|
||
</ul>
|
||
</p></li>
|
||
<li><p><strong>mode</strong> (<a class="reference internal" href="functions.html#int" title="int"><em>int</em></a>) – The Unix file access mode of the file (default: octal <code class="docutils literal notranslate"><span class="pre">0o666</span></code>),
|
||
used only when the database has to be created.</p></li>
|
||
</ul>
|
||
</dd>
|
||
</dl>
|
||
<p><code class="xref py py-class docutils literal notranslate"><span class="pre">ndbm</span></code> objects behave similar to <a class="reference internal" href="../glossary.html#term-mapping"><span class="xref std std-term">mappings</span></a>,
|
||
but <code class="xref py py-meth docutils literal notranslate"><span class="pre">items()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">values()</span></code> methods are not supported.
|
||
The following methods are also provided:</p>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.11: </span>Accepts <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a> for filename.</p>
|
||
</div>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.ndbm.ndbm.close">
|
||
<span class="sig-prename descclassname"><span class="pre">ndbm.</span></span><span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.ndbm.ndbm.close" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Close the NDBM database.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.ndbm.ndbm.clear">
|
||
<span class="sig-prename descclassname"><span class="pre">ndbm.</span></span><span class="sig-name descname"><span class="pre">clear</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.ndbm.ndbm.clear" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Remove all items from the NDBM database.</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 3.13.</span></p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="module-dbm.dumb">
|
||
<span id="dbm-dumb-portable-dbm-implementation"></span><h2><a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a> — Portable DBM implementation<a class="headerlink" href="#module-dbm.dumb" title="Link to this heading">¶</a></h2>
|
||
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/dbm/dumb.py">Lib/dbm/dumb.py</a></p>
|
||
<div class="admonition note" id="index-0">
|
||
<p class="admonition-title">Note</p>
|
||
<p>The <a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a> module is intended as a last resort fallback for the
|
||
<a class="reference internal" href="#module-dbm" title="dbm: Interfaces to various Unix "database" formats."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code></a> module when a more robust module is not available. The <a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a>
|
||
module is not written for speed and is not nearly as heavily used as the other
|
||
database modules.</p>
|
||
</div>
|
||
<hr class="docutils" />
|
||
<p>The <a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a> module provides a persistent <a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate"><span class="pre">dict</span></code></a>-like
|
||
interface which is written entirely in Python.
|
||
Unlike other <a class="reference internal" href="#module-dbm" title="dbm: Interfaces to various Unix "database" formats."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code></a> backends, such as <a class="reference internal" href="#module-dbm.gnu" title="dbm.gnu: GNU database manager (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code></a>, no
|
||
external library is required.</p>
|
||
<p>The <code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code> module defines the following:</p>
|
||
<dl class="py exception">
|
||
<dt class="sig sig-object py" id="dbm.dumb.error">
|
||
<em class="property"><span class="k"><span class="pre">exception</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">dbm.dumb.</span></span><span class="sig-name descname"><span class="pre">error</span></span><a class="headerlink" href="#dbm.dumb.error" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Raised on <a class="reference internal" href="#module-dbm.dumb" title="dbm.dumb: Portable implementation of the simple DBM interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code></a>-specific errors, such as I/O errors. <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> is
|
||
raised for general mapping errors like specifying an incorrect key.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="dbm.dumb.open">
|
||
<span class="sig-prename descclassname"><span class="pre">dbm.dumb.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flag</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'c'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0o666</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#dbm.dumb.open" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Open a <code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code> database.
|
||
The returned database object behaves similar to a <a class="reference internal" href="../glossary.html#term-mapping"><span class="xref std std-term">mapping</span></a>,
|
||
in addition to providing <a class="reference internal" href="#dbm.dumb.dumbdbm.sync" title="dbm.dumb.dumbdbm.sync"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sync()</span></code></a> and <a class="reference internal" href="#dbm.dumb.dumbdbm.close" title="dbm.dumb.dumbdbm.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a>
|
||
methods.</p>
|
||
<dl class="field-list simple">
|
||
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
|
||
<dd class="field-odd"><ul class="simple">
|
||
<li><p><strong>filename</strong> – <p>The basename of the database file (without extensions).
|
||
A new database creates the following files:</p>
|
||
<ul>
|
||
<li><p><code class="file docutils literal notranslate"><em><span class="pre">filename</span></em><span class="pre">.dat</span></code></p></li>
|
||
<li><p><code class="file docutils literal notranslate"><em><span class="pre">filename</span></em><span class="pre">.dir</span></code></p></li>
|
||
</ul>
|
||
</p></li>
|
||
<li><p><strong>flag</strong> (<a class="reference internal" href="stdtypes.html#str" title="str"><em>str</em></a>) – <ul>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'r'</span></code>: Open existing database for reading only.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'w'</span></code>: Open existing database for reading and writing.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'c'</span></code> (default): Open database for reading and writing, creating it if it doesn’t exist.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code>: Always create a new, empty database, open for reading and writing.</p></li>
|
||
</ul>
|
||
</p></li>
|
||
<li><p><strong>mode</strong> (<a class="reference internal" href="functions.html#int" title="int"><em>int</em></a>) – The Unix file access mode of the file (default: octal <code class="docutils literal notranslate"><span class="pre">0o666</span></code>),
|
||
used only when the database has to be created.</p></li>
|
||
</ul>
|
||
</dd>
|
||
</dl>
|
||
<div class="admonition warning">
|
||
<p class="admonition-title">Warning</p>
|
||
<p>It is possible to crash the Python interpreter when loading a database
|
||
with a sufficiently large/complex entry due to stack depth limitations in
|
||
Python’s AST compiler.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.5: </span><a class="reference internal" href="#dbm.dumb.open" title="dbm.dumb.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> always creates a new database when <em>flag</em> is <code class="docutils literal notranslate"><span class="pre">'n'</span></code>.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.8: </span>A database opened read-only if <em>flag</em> is <code class="docutils literal notranslate"><span class="pre">'r'</span></code>.
|
||
A database is not created if it does not exist if <em>flag</em> is <code class="docutils literal notranslate"><span class="pre">'r'</span></code> or <code class="docutils literal notranslate"><span class="pre">'w'</span></code>.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.11: </span><em>filename</em> accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
|
||
</div>
|
||
<p>In addition to the methods provided by the
|
||
<a class="reference internal" href="collections.abc.html#collections.abc.MutableMapping" title="collections.abc.MutableMapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">collections.abc.MutableMapping</span></code></a> class,
|
||
the following methods are provided:</p>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.dumb.dumbdbm.sync">
|
||
<span class="sig-prename descclassname"><span class="pre">dumbdbm.</span></span><span class="sig-name descname"><span class="pre">sync</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.dumb.dumbdbm.sync" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Synchronize the on-disk directory and data files. This method is called
|
||
by the <a class="reference internal" href="shelve.html#shelve.Shelf.sync" title="shelve.Shelf.sync"><code class="xref py py-meth docutils literal notranslate"><span class="pre">shelve.Shelf.sync()</span></code></a> method.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="dbm.dumb.dumbdbm.close">
|
||
<span class="sig-prename descclassname"><span class="pre">dumbdbm.</span></span><span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#dbm.dumb.dumbdbm.close" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Close the database.</p>
|
||
</dd></dl>
|
||
|
||
</dd></dl>
|
||
|
||
</section>
|
||
</section>
|
||
|
||
|
||
<div class="clearer"></div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sphinxsidebar" role="navigation" aria-label="Main">
|
||
<div class="sphinxsidebarwrapper">
|
||
<div>
|
||
<h3><a href="../contents.html">Table of Contents</a></h3>
|
||
<ul>
|
||
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm</span></code> — Interfaces to Unix “databases”</a><ul>
|
||
<li><a class="reference internal" href="#module-dbm.sqlite3"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.sqlite3</span></code> — SQLite backend for dbm</a></li>
|
||
<li><a class="reference internal" href="#module-dbm.gnu"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.gnu</span></code> — GNU database manager</a></li>
|
||
<li><a class="reference internal" href="#module-dbm.ndbm"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.ndbm</span></code> — New Database Manager</a></li>
|
||
<li><a class="reference internal" href="#module-dbm.dumb"><code class="xref py py-mod docutils literal notranslate"><span class="pre">dbm.dumb</span></code> — Portable DBM implementation</a></li>
|
||
</ul>
|
||
</li>
|
||
</ul>
|
||
|
||
</div>
|
||
<div>
|
||
<h4>Previous topic</h4>
|
||
<p class="topless"><a href="marshal.html"
|
||
title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">marshal</span></code> — Internal Python object serialization</a></p>
|
||
</div>
|
||
<div>
|
||
<h4>Next topic</h4>
|
||
<p class="topless"><a href="sqlite3.html"
|
||
title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">sqlite3</span></code> — DB-API 2.0 interface for SQLite databases</a></p>
|
||
</div>
|
||
<div role="note" aria-label="source link">
|
||
<h3>This Page</h3>
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