<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>7.12 bsddb -- Interface to Berkeley DB library</title>
<META NAME="description" CONTENT="7.12 bsddb -- Interface to Berkeley DB library">
<META NAME="keywords" CONTENT="lib">
<META NAME="resource-type" CONTENT="document">
<META NAME="distribution" CONTENT="global">
<meta http-equiv="Content-Type" content="text/html; charset=">
<link rel="STYLESHEET" href="lib.css">
<link rel="first" href="lib.html">
<link rel="contents" href="contents.html" title="Contents">
<link rel="index" href="genindex.html" title="Index">
<LINK REL="next" href="module-zlib.html">
<LINK REL="previous" href="module-whichdb.html">
<LINK REL="up" href="someos.html">
<LINK REL="next" href="bsddb-objects.html">
</head>
<body>
<DIV CLASS="navigation">
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td><A href="module-whichdb.html"><img src="../icons/previous.gif"
border="0" height="32"
alt="Previous Page" width="32"></A></td>
<td><A href="someos.html"><img src="../icons/up.gif"
border="0" height="32"
alt="Up One Level" width="32"></A></td>
<td><A href="bsddb-objects.html"><img src="../icons/next.gif"
border="0" height="32"
alt="Next Page" width="32"></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td><A href="contents.html"><img src="../icons/contents.gif"
border="0" height="32"
alt="Contents" width="32"></A></td>
<td><a href="modindex.html" title="Module Index"><img src="../icons/modules.gif"
border="0" height="32"
alt="Module Index" width="32"></a></td>
<td><A href="genindex.html"><img src="../icons/index.gif"
border="0" height="32"
alt="Index" width="32"></A></td>
</tr></table>
<b class="navlabel">Previous:</b> <a class="sectref" href="module-whichdb.html">7.11 whichdb </A>
<b class="navlabel">Up:</b> <a class="sectref" href="someos.html">7. Optional Operating System</A>
<b class="navlabel">Next:</b> <a class="sectref" href="bsddb-objects.html">7.12.1 Hash, BTree and</A>
<br><hr>
</DIV>
<!--End of Navigation Panel-->
<H1><A NAME="SECTION0091200000000000000000">
7.12 <tt class="module">bsddb</tt> --
Interface to Berkeley DB library</A>
</H1>
<P>
<p class="availability">Availability: <span
class="platform">Unix, Windows</span>.</p>
<P>
The <tt class="module">bsddb</tt> module provides an interface to the Berkeley DB
library. Users can create hash, btree or record based library files
using the appropriate open call. Bsddb objects behave generally like
dictionaries. Keys and values must be strings, however, so to use
other objects as keys or to store other kinds of objects the user must
serialize them somehow, typically using marshal.dumps or pickle.dumps.
<P>
There are two incompatible versions of the underlying library.
Version 1.85 is widely available, but has some known bugs. Version 2
is not quite as widely used, but does offer some improvements. The
<tt class="module">bsddb</tt> module uses the 1.85 interface. Starting with Python
2.0, the <b class="program">configure</b> script can usually determine the
version of the library which is available and build it correctly. If
you have difficulty getting <b class="program">configure</b> to do the right thing,
run it with the <b class="programopt">--help</b> option to get information about
additional options that can help. On Windows, you will need to define
the <code>HAVE_DB_185_H</code> macro if you are building Python from source
and using version 2 of the DB library.
<P>
The <tt class="module">bsddb</tt> module defines the following functions that create
objects that access the appropriate type of Berkeley DB file. The
first two arguments of each function are the same. For ease of
portability, only the first two arguments should be used in most
instances.
<P>
<dl><dt><b><a name="l2h-2032"><tt class="function">hashopen</tt></a></b>(<var>filename</var><big>[</big><var>, flag</var><big>[</big><var>,
mode</var><big>[</big><var>, bsize</var><big>[</big><var>,
ffactor</var><big>[</big><var>, nelem</var><big>[</big><var>,
cachesize</var><big>[</big><var>, hash</var><big>[</big><var>,
lorder</var><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big>)
<dd>
Open the hash format file named <var>filename</var>. The optional
<var>flag</var> identifies the mode used to open the file. It may be
"<tt class="character">r</tt>" (read only), "<tt class="character">w</tt>" (read-write),
"<tt class="character">c</tt>" (read-write - create if necessary) or
"<tt class="character">n</tt>" (read-write - truncate to zero length). The other
arguments are rarely used and are just passed to the low-level
<tt class="cfunction">dbopen()</tt> function. Consult the Berkeley DB documentation
for their use and interpretation.
</dl>
<P>
<dl><dt><b><a name="l2h-2033"><tt class="function">btopen</tt></a></b>(<var>filename</var><big>[</big><var>, flag</var><big>[</big><var>,
mode</var><big>[</big><var>, btflags</var><big>[</big><var>, cachesize</var><big>[</big><var>, maxkeypage</var><big>[</big><var>,
minkeypage</var><big>[</big><var>, psize</var><big>[</big><var>, lorder</var><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big>)
<dd>
<P>
Open the btree format file named <var>filename</var>. The optional
<var>flag</var> identifies the mode used to open the file. It may be
"<tt class="character">r</tt>" (read only), "<tt class="character">w</tt>" (read-write),
"<tt class="character">c</tt>" (read-write - create if necessary) or
"<tt class="character">n</tt>" (read-write - truncate to zero length). The other
arguments are rarely used and are just passed to the low-level dbopen
function. Consult the Berkeley DB documentation for their use and
interpretation.
</dl>
<P>
<dl><dt><b><a name="l2h-2034"><tt class="function">rnopen</tt></a></b>(<var>filename</var><big>[</big><var>, flag</var><big>[</big><var>, mode</var><big>[</big><var>,
rnflags</var><big>[</big><var>, cachesize</var><big>[</big><var>, psize</var><big>[</big><var>, lorder</var><big>[</big><var>,
reclen</var><big>[</big><var>, bval</var><big>[</big><var>, bfname</var><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big><big>]</big>)
<dd>
<P>
Open a DB record format file named <var>filename</var>. The optional
<var>flag</var> identifies the mode used to open the file. It may be
"<tt class="character">r</tt>" (read only), "<tt class="character">w</tt>" (read-write),
"<tt class="character">c</tt>" (read-write - create if necessary) or
"<tt class="character">n</tt>" (read-write - truncate to zero length). The other
arguments are rarely used and are just passed to the low-level dbopen
function. Consult the Berkeley DB documentation for their use and
interpretation.
</dl>
<P>
<div class="seealso">
<p class="heading"><b>See Also:</b></p>
<dl compact class="seemodule">
<dt>Module <b><tt class="module"><a href="module-dbhash.html">dbhash</a></tt>:</b>
<dd>DBM-style interface to the <tt class="module">bsddb</tt>.
</dl>
</div>
<P>
<p><hr>
<!--Table of Child-Links-->
<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
<UL CLASS="ChildLinks">
<LI><A href="bsddb-objects.html">7.12.1 Hash, BTree and Record Objects</a>
</ul>
<!--End of Table of Child-Links-->
<DIV CLASS="navigation">
<p><hr>
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td><A href="module-whichdb.html"><img src="../icons/previous.gif"
border="0" height="32"
alt="Previous Page" width="32"></A></td>
<td><A href="someos.html"><img src="../icons/up.gif"
border="0" height="32"
alt="Up One Level" width="32"></A></td>
<td><A href="bsddb-objects.html"><img src="../icons/next.gif"
border="0" height="32"
alt="Next Page" width="32"></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td><A href="contents.html"><img src="../icons/contents.gif"
border="0" height="32"
alt="Contents" width="32"></A></td>
<td><a href="modindex.html" title="Module Index"><img src="../icons/modules.gif"
border="0" height="32"
alt="Module Index" width="32"></a></td>
<td><A href="genindex.html"><img src="../icons/index.gif"
border="0" height="32"
alt="Index" width="32"></A></td>
</tr></table>
<b class="navlabel">Previous:</b> <a class="sectref" href="module-whichdb.html">7.11 whichdb </A>
<b class="navlabel">Up:</b> <a class="sectref" href="someos.html">7. Optional Operating System</A>
<b class="navlabel">Next:</b> <a class="sectref" href="bsddb-objects.html">7.12.1 Hash, BTree and</A>
<hr>
<span class="release-info">Release 2.2, documentation updated on December 21, 2001.</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>
