<!--$Id: db_del.so,v 10.51 2007/10/24 16:06:06 bostic Exp $--> <!--Copyright (c) 1997,2008 Oracle. 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,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td> <b>DB->del</b> </td> <td align=right> <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></td> </tr></table> <hr size=1 noshade> <tt> <b><pre> #include <db.h> <p> int DB->del(DB *db, DB_TXN *txnid, DBT *key, u_int32_t flags); </pre></b> <hr size=1 noshade> <b>Description: DB->del</b> <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> <b>Parameters</b> <br> <b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul> <b>key</b><ul compact><li>The key <a href="../api_c/dbt_class.html">DBT</a> operated on.</ul> <b>txnid</b><ul compact><li>If the operation is part of an application-specified transaction, the <b>txnid</b> parameter is a transaction handle returned from <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 <b>txnid</b> parameter is a handle returned from <a href="../api_c/env_cdsgroup_begin.html">DB_ENV->cdsgroup_begin</a>; otherwise NULL. If no transaction handle is specified, but the operation occurs in a transactional database, the operation will be implicitly transaction protected. </ul> <br> <br><b>Errors</b> <p>The DB->del method may fail and return one of the following non-zero errors:</p> <br> <b>DB_LOCK_DEADLOCK</b><ul compact><li>A transactional database environment operation was selected to resolve a deadlock.</ul> <b>DB_LOCK_NOTGRANTED</b><ul compact><li>A Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable to grant a lock in the allowed time.</ul> <br> <br> <b>DB_REP_HANDLE_DEAD</b><ul compact><li>The database handle has been invalidated because a replication election unrolled a committed transaction.</ul> <br> <br> <b>DB_REP_LOCKOUT</b><ul compact><li>The operation was blocked by client/master synchronization.</ul> <br> <br> <b>DB_SECONDARY_BAD</b><ul compact><li>A secondary index references a nonexistent primary key.</ul> <br> <br> <b>EACCES</b><ul compact><li>An attempt was made to modify a read-only database.</ul> <br> <br> <b>EINVAL</b><ul compact><li>An invalid flag value or parameter was specified.</ul> <br> <hr size=1 noshade> <br><b>Class</b> <a href="../api_c/db_class.html">DB</a> <br><b>See Also</b> <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_core.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>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> </body> </html>