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310 lines
11 KiB
HTML
<?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>DBcursor->del()</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 C API Reference" />
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<link rel="up" href="dbc.html" title="Chapter 3. The DBcursor Handle" />
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<link rel="prev" href="dbccount.html" title="DBcursor->count()" />
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<link rel="next" href="dbcdup.html" title="DBcursor->dup()" />
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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">DBcursor->del()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="dbccount.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 3.
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The DBcursor Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="dbcdup.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="dbcdel"></a>DBcursor->del()</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db.h>
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int
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DBcursor->del(DBC *DBcursor, u_int32_t flags); </pre>
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<p>
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The <code class="methodname">DBcursor->del()</code> method deletes the key/data pair to which the
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cursor refers.
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</p>
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<p>
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When called on a cursor opened on a database that has been made into a
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secondary index using the
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<a class="xref" href="dbassociate.html" title="DB->associate()">DB->associate()</a> method, the
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<a class="xref" href="dbdel.html" title="DB->del()">DB->del()</a> method deletes
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the key/data pair from the primary database and all secondary indices.
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</p>
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<p>
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The cursor position is unchanged after a delete, and subsequent calls
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to cursor functions expecting the cursor to refer to an existing key
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will fail.
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</p>
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<p>
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The <code class="methodname">DBcursor->del()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_KEYEMPTY" class="olink">DB_KEYEMPTY</a> if
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the element has already been deleted. The <code class="methodname">DBcursor->del()</code>
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<span>
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<span>
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method returns a non-zero error value on failure and 0 on success.
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</span>
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</span>
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</p>
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<div class="sect2" 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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<h3 class="title"><a id="id3696908"></a>Parameters</h3>
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</div>
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</div>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3696587"></a>flags</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>flags</strong></span> parameter must be set to 0
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or one of the following values:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p><a id="dbcput_DB_CONSUME"></a>
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<code class="literal">DB_CONSUME</code>
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</p>
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<p>
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If the database is of type DB_QUEUE then this flag may be set to force the head of the queue
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to move to the first non-deleted item in the queue. Normally this is only done if the
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deleted item is exactly at the head when deleted.
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</p>
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</li>
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</ul>
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</div>
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</div>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="id3697133"></a>Errors</h3>
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</div>
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</div>
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</div>
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<p>
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The <code class="methodname">DBcursor->del()</code> <span>
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<span>
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method may fail and return one of the following non-zero errors:
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</span>
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</span>
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</p>
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<div class="sect3" 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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<h4 class="title"><a id="id3697214"></a>DB_FOREIGN_CONFLICT</h4>
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</div>
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</div>
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</div>
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<p>
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A <a class="link" href="dbassociate_foreign.html" title="DB->associate_foreign()">foreign key constraint violation</a>
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has occurred. This can be caused by one of two things:
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</p>
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<div class="orderedlist">
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<ol type="1">
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<li>
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<p>
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An attempt was made to add a record to a
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constrained database, and the key used for that
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record does not exist in the foreign key
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database.
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</p>
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</li>
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<li>
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<p>
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<a class="link" href="dbassociate_foreign.html#associate_foreign_DB_FOREIGN_ABORT">DB_FOREIGN_ABORT</a>
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was declared for a foreign key database, and then
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subsequently a record was deleted from the
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foreign key database without first removing it
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from the constrained secondary database.
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</p>
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</li>
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</ol>
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</div>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3696812"></a>DB_LOCK_DEADLOCK</h4>
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</div>
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</div>
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</div>
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<p>
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A transactional database environment operation was selected to resolve
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a deadlock.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3696362"></a>DB_LOCK_NOTGRANTED</h4>
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</div>
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</div>
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</div>
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<p>
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A Berkeley DB Concurrent Data Store database environment configured
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for lock timeouts was unable to grant a lock in the allowed time.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3697079"></a> DB_REP_HANDLE_DEAD</h4>
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</div>
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</div>
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</div>
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<p>
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When a client synchronizes with the master, it is possible for committed
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transactions to be rolled back. This invalidates all the database and cursor
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handles opened in the replication environment. Once this occurs, an attempt to use
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such a handle will
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return <code class="literal">DB_REP_HANDLE_DEAD</code>.
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The application will need to discard the handle and open a new one in order to
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continue processing.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3697262"></a>DB_REP_LOCKOUT</h4>
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</div>
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</div>
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</div>
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<p>
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The operation was blocked by client/master synchronization.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3697240"></a>DB_SECONDARY_BAD</h4>
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</div>
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</div>
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</div>
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<p>
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A secondary index references a nonexistent primary key.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3696400"></a>EACCES</h4>
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</div>
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</div>
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</div>
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<p>
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An attempt was made to modify a read-only database.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3697394"></a>EINVAL</h4>
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</div>
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</div>
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</div>
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<p>
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If the cursor has not been initialized; or if an invalid flag value or parameter was specified.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="id3697401"></a>EPERM</h4>
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</div>
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</div>
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</div>
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<p>
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Write attempted on read-only cursor when the
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<a class="link" href="envopen.html#envopen_DB_INIT_CDB">DB_INIT_CDB</a>
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flag was specified to <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a>.
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</p>
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</div>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="id3697162"></a>Class</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="link" href="dbc.html" title="Chapter 3. The DBcursor Handle">DBcursor</a>
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</p>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="id3696758"></a>See Also</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="xref" href="dbc.html#dbclist" title="Database Cursors and Related Methods">Database Cursors and Related Methods</a>
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</p>
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</div>
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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="dbccount.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="dbc.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="dbcdup.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">DBcursor->count() </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"> DBcursor->dup()</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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