<!--$Id: db_del.so,v 10.49 2006/09/13 14:30:52 mjc Exp $--> <!--Copyright (c) 1997,2007 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> <h3>Db::del</h3> </td> <td align=right> <a href="../api_cxx/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> <h3><pre> #include <db_cxx.h> <p> int Db::del(DbTxn *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_cxx/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 either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>flags</b><dd>The <b>flags</b> parameter is currently unused, and must be set to 0. <dt><b>key</b><dd>The key <a href="../api_cxx/dbt_class.html">Dbt</a> operated on. <dt><b>txnid</b><dd>If the operation is part of an application-specified transaction, the <b>txnid</b> parameter is a transaction handle returned from <a href="../api_cxx/txn_begin.html">DbEnv::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_cxx/env_cdsgroup_begin.html">DbEnv::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. </dl> <h3>Errors</h3> <p>The Db::del method may fail and throw <a href="../api_cxx/except_class.html">DbException</a>, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:</p> <dl compact> <dt>DB_REP_HANDLE_DEAD<dd>The database handle has been invalidated because a replication election unrolled a committed transaction. <dt>DB_REP_LOCKOUT<dd>The operation was blocked by client/master synchronization. </dl> <dl compact> <dt>DB_SECONDARY_BAD<dd>A secondary index references a nonexistent primary key. </dl> <dl compact> <dt>EACCES<dd>An attempt was made to modify a read-only database. </dl> <dl compact> <dt>EINVAL<dd>An invalid flag value or parameter was specified. </dl> <p>If a transactional database environment operation was selected to resolve a deadlock, the Db::del method will fail and either return <a href="../ref/program/errorret.html#DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK</a> or throw a <a href="../api_cxx/deadlock_class.html">DbDeadlockException</a> exception.</p> <p>If a Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable to grant a lock in the allowed time, the Db::del method will fail and either return <a href="../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception.</p> <hr size=1 noshade> <h3>Class</h3> <a href="../api_cxx/db_class.html">Db</a> <h3>See Also</h3> <a href="../api_cxx/db_list.html">Databases and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_cxx/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) 1996,2007 Oracle. All rights reserved.</font> </body> </html>