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<!--$Id: db_del.so,v 10.49 2006/09/13 14:30:52 mjc Exp $-->
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<h3>DB->del</h3>
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<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>
<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_c/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_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.
</dl>
<h3>Errors</h3>
<p>The DB->del method
may fail and return one of the following non-zero errors:</p>
<dl compact>
<dt>DB_LOCK_DEADLOCK<dd>A transactional database environment operation was selected to resolve
a deadlock.
<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>
<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>
<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>
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