<!--$Id: db_del.html,v 1.2 2004/03/30 01:21:42 jtownsen Exp $--> <!--Copyright 1997-2003 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB->del</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <a name="2"><!--meow--></a> <table width="100%"><tr valign=top> <td> <h3>DB->del</h3> </td> <td align=right> <a href="../api_c/api_index.html"><img src="../images/api.gif" alt="API"></a> <a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db.h> <p> int DB->del(DB *db, DB_TXN *txnid, DBT *key, u_int32_t flags); </pre></h3> <hr size=1 noshade> <h3>Description: DB->del</h3> <p>The DB->del method removes key/data pairs from the database. The key/data pair associated with the specified <b>key</b> is discarded from the database. In the presence of duplicate key values, all records associated with the designated key will be discarded.</p> <p>When called on a database that has been made into a secondary index using the <a href="../api_c/db_associate.html">DB->associate</a> method, the DB->del method deletes the key/data pair from the primary database and all secondary indices.</p> <p> The DB->del method will return <a href="../ref/program/errorret.html#DB_NOTFOUND">DB_NOTFOUND</a> if the specified key is not in the database. The DB->del method will return <a href="../ref/program/errorret.html#DB_KEYEMPTY">DB_KEYEMPTY</a> if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted. Unless otherwise specified, the DB->del method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <p><dl compact> <p><dt><b>key</b><dd> The key <a href="../api_c/dbt_class.html">DBT</a> operated on. <p><dt><b>flags</b><dd> The <b>flags</b> parameter must be set to 0 or the following value: <p><dl compact> <p><dt><a name="DB_AUTO_COMMIT">DB_AUTO_COMMIT</a><dd>Enclose the DB->del call within a transaction. If the call succeeds, changes made by the operation will be recoverable. If the call fails, the operation will have made no changes. </dl> <p><dt><b>txnid</b><dd> If the operation is to be transaction-protected, (other than by specifying the DB_AUTO_COMMIT flag), the <b>txnid</b> parameter is a transaction handle returned from <a href="../api_c/txn_begin.html">DB_ENV->txn_begin</a>; otherwise, NULL. </dl> <h3>Errors</h3> <p>The DB->del method may fail and return one of the following non-zero errors:</p> <p><dl compact> <p><dt>DB_LOCK_DEADLOCK<dd>A transactional database environment operation was selected to resolve a deadlock. <p><dt>DB_LOCK_NOTGRANTED<dd>A Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable to grant a lock in the allowed time. </dl> <p><dl compact> <p><dt>DB_REP_HANDLE_DEAD<dd>The database handle has been invalidated because a replication election unrolled a committed transaction. </dl> <p><dl compact> <p><dt>DB_SECONDARY_BAD<dd>A secondary index references a nonexistent primary key. </dl> <p><dl compact> <p><dt>EACCES<dd>An attempt was made to modify a read-only database. </dl> <p><dl compact> <p><dt>EINVAL<dd>An invalid flag value or parameter was specified. </dl> <hr size=1 noshade> <h3>Class</h3> <a href="../api_c/db_class.html">DB</a> <h3>See Also</h3> <a href="../api_c/db_list.html">Databases and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_c/api_index.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1><a href="../sleepycat/legal.html">Copyright (c) 1996-2003</a> <a href="http://www.sleepycat.com">Sleepycat Software, Inc.</a> - All rights reserved.</font> </body> </html>