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2.2 KiB
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<!--$Id: curdup.so,v 11.5 2000/12/19 14:45:39 sue Exp $-->
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<!--Copyright 1997, 1998, 1999, 2000 by Sleepycat Software, Inc.-->
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<!--All rights reserved.-->
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<html>
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<head>
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<title>Berkeley DB Reference Guide: Duplicating a cursor</title>
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<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
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<meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++">
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<body bgcolor=white>
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<a name="2"><!--meow--></a> <a name="3"><!--meow--></a>
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<table><tr valign=top>
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<td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Access Methods</dl></h3></td>
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<td width="1%"><a href="../../ref/am/curdel.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../ref/toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/am/join.html"><img src="../../images/next.gif" alt="Next"></a>
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</td></tr></table>
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<p>
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<h1 align=center>Duplicating a cursor</h1>
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<p>Once a cursor has been initialized (e.g., by a call to <a href="../../api_c/dbc_get.html">DBcursor->c_get</a>),
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it can be thought of as identifying a particular location in a database.
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The <a href="../../api_c/dbc_dup.html">DBcursor->c_dup</a> function permits an application to create a new cursor that
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has the same locking and transactional information as the cursor from
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which it is copied, and which optionally refers to the same position in
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the database.
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<p>In order to maintain a cursor position when an application is using
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locking, locks are maintained on behalf of the cursor until the cursor is
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closed. In cases when an application is using locking without
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transactions, cursor duplication is often required to avoid
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self-deadlocks. For further details, refer to
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<a href="../../ref/lock/am_conv.html">Access method locking conventions</a>.
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<table><tr><td><br></td><td width="1%"><a href="../../ref/am/curdel.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../ref/toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/am/join.html"><img src="../../images/next.gif" alt="Next"></a>
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<p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font>
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