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HTML
94 lines
4.1 KiB
HTML
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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>db join</title>
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<link rel="stylesheet" href="apiReference.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB TCL API Reference" />
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<link rel="up" href="tclapi.html" title="Chapter 1. Berkeley DB Tcl APIs" />
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<link rel="prev" href="db_is_byteswapped.html" title="db is_byteswapped" />
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<link rel="next" href="db_open.html" title="berkdb open" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 11.2.5.2</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center"><span xmlns="http://www.w3.org/1999/xhtml" class="emphasis"><em>db</em></span> join</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="db_is_byteswapped.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 1.
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Berkeley DB Tcl APIs
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="db_open.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="db_join"></a><span class="emphasis"><em>db</em></span> join</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">db join
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<span class="emphasis"><em>db.cX</em></span>
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<span class="emphasis"><em>db.cY</em></span>
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<span class="emphasis"><em>db.cZ</em></span>
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... </pre>
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<p>
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The <span class="emphasis"><em>db</em></span> <span class="bold"><strong>join</strong></span>
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command joins the specified cursors and returns a cursor handle that
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can be used to iterate through the joined {key data} pairs. The
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returned cursor handle is bound to a Tcl command of the form <span class="bold"><strong>dbN.cX</strong></span>, where X is an integer starting at 0
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(for example, db0.c0 and db0.c1). It is through this Tcl command that
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the script accesses the cursor methods.
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</p>
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<p>
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The returned join cursor has limited cursor functionality, and only
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the <span class="emphasis"><em>dbc</em></span> <span class="bold"><strong>get</strong></span> and
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<span class="emphasis"><em>dbc</em></span> <span class="bold"><strong>close</strong></span>
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commands will succeed.
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</p>
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<p>
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See <a href="../../programmer_reference/am_cursor.html#am_join" class="olink">Equality Join</a>
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in the <em class="citetitle">Berkeley DB Programmer's Reference Guide</em> for more
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information on the underlying requirements for joining.
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</p>
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<p>
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In a transaction-protected environment, all the cursors listed must
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have been created within the same transaction.
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</p>
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<p>
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In the case of error, a Tcl error is thrown.
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</p>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="db_is_byteswapped.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="tclapi.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="db_open.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top"><span class="emphasis"><em>db</em></span> is_byteswapped </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top"> berkdb open</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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