File: //usr/share/doc/python-docs-2.4.3/html/lib/module-dumbdbm.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<link rel="STYLESHEET" href="lib.css" type='text/css' />
<link rel="SHORTCUT ICON" href="../icons/pyfav.png" type="image/png" />
<link rel='start' href='../index.html' title='Python Documentation Index' />
<link rel="first" href="lib.html" title='Python Library Reference' />
<link rel='contents' href='contents.html' title="Contents" />
<link rel='index' href='genindex.html' title='Index' />
<link rel='last' href='about.html' title='About this document...' />
<link rel='help' href='about.html' title='About this document...' />
<link rel="next" href="module-zlib.html" />
<link rel="prev" href="module-bsddb.html" />
<link rel="parent" href="someos.html" />
<link rel="next" href="dumbdbm-objects.html" />
<meta name='aesop' content='information' />
<title>7.14 dumbdbm -- Portable DBM implementation</title>
</head>
<body>
<DIV CLASS="navigation">
<div id='top-navigation-panel' xml:id='top-navigation-panel'>
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="7.13.1 Hash, BTree and"
href="bsddb-objects.html"><img src='../icons/previous.png'
border='0' height='32' alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="7. Optional Operating System"
href="someos.html"><img src='../icons/up.png'
border='0' height='32' alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="7.14.1 Dumbdbm Objects"
href="dumbdbm-objects.html"><img src='../icons/next.png'
border='0' height='32' alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
href="contents.html"><img src='../icons/contents.png'
border='0' height='32' alt='Contents' width='32' /></A></td>
<td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png'
border='0' height='32' alt='Module Index' width='32' /></a></td>
<td class='online-navigation'><a rel="index" title="Index"
href="genindex.html"><img src='../icons/index.png'
border='0' height='32' alt='Index' width='32' /></A></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="bsddb-objects.html">7.13.1 Hash, BTree and</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="someos.html">7. Optional Operating System</A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="dumbdbm-objects.html">7.14.1 Dumbdbm Objects</A>
</div>
<hr /></div>
</DIV>
<!--End of Navigation Panel-->
<H1><A NAME="SECTION0091400000000000000000">
7.14 <tt class="module">dumbdbm</tt> --
Portable DBM implementation</A>
</H1>
<P>
<A NAME="module-dumbdbm"></A>
<P>
<a id='l2h-2812' xml:id='l2h-2812'></a>
<P>
<div class="note"><b class="label">Note:</b>
The <tt class="module">dumbdbm</tt> module is intended as a last resort fallback for
the <tt class="module"><a href="module-anydbm.html">anydbm</a></tt> module when no more robust module is available.
The <tt class="module">dumbdbm</tt> module is not written for speed and is not nearly as
heavily used as the other database modules.
</div>
<P>
The <tt class="module">dumbdbm</tt> module provides a persistent dictionary-like interface
which is written entirely in Python. Unlike other modules such as
<tt class="module"><a href="module-gdbm.html">gdbm</a></tt> and <tt class="module"><a href="module-bsddb.html">bsddb</a></tt>, no external library is required. As
with other persistent mappings, the keys and values must always be strings.
<P>
The module defines the following:
<P>
<dl><dt><b><span class="typelabel">exception</span> <tt id='l2h-2810' xml:id='l2h-2810' class="exception">error</tt></b></dt>
<dd>
Raised on dumbdbm-specific errors, such as I/O errors. <tt class="exception">KeyError</tt>
is raised for general mapping errors like specifying an incorrect key.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
<td><nobr><b><tt id='l2h-2811' xml:id='l2h-2811' class="function">open</tt></b>(</nobr></td>
<td><var>filename</var><big>[</big><var>, flag</var><big>[</big><var>, mode</var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
Open a dumbdbm database and return a dumbdbm object. The <var>filename</var>
argument is the basename of the database file (without any specific
extensions). When a dumbdbm database is created, files with <span class="file">.dat</span> and
<span class="file">.dir</span> extensions are created.
<P>
The optional <var>flag</var> argument is currently ignored; the database is
always opened for update, and will be created if it does not exist.
<P>
The optional <var>mode</var> argument is the <span class="Unix">Unix</span> mode of the file, used
only when the database has to be created. It defaults to octal
<code>0666</code> (and will be modified by the prevailing umask).
<span class="versionnote">Changed in version 2.2:
The <var>mode</var> argument was ignored in earlier
versions.</span>
</dl>
<P>
<div class="seealso">
<p class="heading">See Also:</p>
<dl compact="compact" class="seemodule">
<dt>Module <b><tt class="module"><a href="module-anydbm.html">anydbm</a></tt>:</b>
<dd>Generic interface to <code>dbm</code>-style databases.
</dl>
<dl compact="compact" class="seemodule">
<dt>Module <b><tt class="module"><a href="module-dbm.html">dbm</a></tt>:</b>
<dd>Similar interface to the DBM/NDBM library.
</dl>
<dl compact="compact" class="seemodule">
<dt>Module <b><tt class="module"><a href="module-gdbm.html">gdbm</a></tt>:</b>
<dd>Similar interface to the GNU GDBM library.
</dl>
<dl compact="compact" class="seemodule">
<dt>Module <b><tt class="module"><a href="module-shelve.html">shelve</a></tt>:</b>
<dd>Persistence module which stores non-string data.
</dl>
<dl compact="compact" class="seemodule">
<dt>Module <b><tt class="module"><a href="module-whichdb.html">whichdb</a></tt>:</b>
<dd>Utility module used to determine the type of an
existing database.
</dl>
</div>
<P>
<p><br /></p><hr class='online-navigation' />
<div class='online-navigation'>
<!--Table of Child-Links-->
<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
<UL CLASS="ChildLinks">
<LI><A href="dumbdbm-objects.html">7.14.1 Dumbdbm Objects</a>
</ul>
<!--End of Table of Child-Links-->
</div>
<DIV CLASS="navigation">
<div class='online-navigation'>
<p></p><hr />
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="7.13.1 Hash, BTree and"
href="bsddb-objects.html"><img src='../icons/previous.png'
border='0' height='32' alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="7. Optional Operating System"
href="someos.html"><img src='../icons/up.png'
border='0' height='32' alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="7.14.1 Dumbdbm Objects"
href="dumbdbm-objects.html"><img src='../icons/next.png'
border='0' height='32' alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
href="contents.html"><img src='../icons/contents.png'
border='0' height='32' alt='Contents' width='32' /></A></td>
<td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png'
border='0' height='32' alt='Module Index' width='32' /></a></td>
<td class='online-navigation'><a rel="index" title="Index"
href="genindex.html"><img src='../icons/index.png'
border='0' height='32' alt='Index' width='32' /></A></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="bsddb-objects.html">7.13.1 Hash, BTree and</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="someos.html">7. Optional Operating System</A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="dumbdbm-objects.html">7.14.1 Dumbdbm Objects</A>
</div>
</div>
<hr />
<span class="release-info">Release 2.4.3, documentation updated on 29 March 2006.</span>
</DIV>
<!--End of Navigation Panel-->
<ADDRESS>
See <i><a href="about.html">About this document...</a></i> for information on suggesting changes.
</ADDRESS>
</BODY>
</HTML>