1<!--$Id: db_del.so,v 10.51 2007/10/24 16:06:06 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: DB->del</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>DB->del</b> 14</td> 15<td align=right> 16<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a> 17<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db.h> 23<p> 24int 25DB->del(DB *db, DB_TXN *txnid, DBT *key, u_int32_t flags); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: DB->del</b> 29<p>The DB->del method removes key/data pairs from the database. The 30key/data pair associated with the specified <b>key</b> is discarded from 31the database. In the presence of duplicate key values, all records 32associated with the designated key will be discarded.</p> 33<p>When called on a database that has been made into a secondary index 34using the <a href="../api_c/db_associate.html">DB->associate</a> method, the DB->del method deletes the 35key/data pair from the primary database and all secondary indices.</p> 36<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. 37The 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 38the specified key exists, but was never explicitly created by the 39application or was later deleted. 40Unless otherwise specified, the DB->del method 41returns a non-zero error value on failure 42and 0 on success. 43</p> 44<b>Parameters</b> <br> 45 <b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul> 46 <b>key</b><ul compact><li>The key <a href="../api_c/dbt_class.html">DBT</a> operated on.</ul> 47 <b>txnid</b><ul compact><li>If the operation is part of an application-specified transaction, the 48<b>txnid</b> parameter is a transaction handle returned from 49<a href="../api_c/txn_begin.html">DB_ENV->txn_begin</a>; if the operation is part of a Berkeley DB Concurrent Data Store group, the 50<b>txnid</b> parameter is a handle returned from 51<a href="../api_c/env_cdsgroup_begin.html">DB_ENV->cdsgroup_begin</a>; otherwise NULL. 52If no transaction handle is 53specified, but the 54operation occurs in a transactional 55database, 56the operation will be implicitly transaction protected. 57</ul> 58<br> 59<br><b>Errors</b> 60<p>The DB->del method 61may fail and return one of the following non-zero errors:</p> 62<br> 63<b>DB_LOCK_DEADLOCK</b><ul compact><li>A transactional database environment operation was selected to resolve 64a deadlock.</ul> 65<b>DB_LOCK_NOTGRANTED</b><ul compact><li>A Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable 66to grant a lock in the allowed time.</ul> 67<br> 68<br> 69<b>DB_REP_HANDLE_DEAD</b><ul compact><li>The database handle has been invalidated because a replication election 70unrolled a committed transaction.</ul> 71<br> 72<br> 73<b>DB_REP_LOCKOUT</b><ul compact><li>The operation was blocked by client/master synchronization.</ul> 74<br> 75<br> 76<b>DB_SECONDARY_BAD</b><ul compact><li>A secondary index references a nonexistent primary key.</ul> 77<br> 78<br> 79<b>EACCES</b><ul compact><li>An attempt was made to modify a read-only database.</ul> 80<br> 81<br> 82<b>EINVAL</b><ul compact><li>An 83invalid flag value or parameter was specified.</ul> 84<br> 85<hr size=1 noshade> 86<br><b>Class</b> 87<a href="../api_c/db_class.html">DB</a> 88<br><b>See Also</b> 89<a href="../api_c/db_list.html">Databases and Related Methods</a> 90</tt> 91<table width="100%"><tr><td><br></td><td align=right> 92<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 93</td></tr></table> 94<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 95</body> 96</html> 97
