1<!--$Id: db_truncate.so,v 1.29 2006/09/13 14:30:52 mjc 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->truncate</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->truncate</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->truncate(DB *db, 26 DB_TXN *txnid, u_int32_t *countp, u_int32_t flags); 27</pre></b> 28<hr size=1 noshade> 29<b>Description: DB->truncate</b> 30<p>The DB->truncate method empties the database, discarding all records 31it contains. The number of records discarded from the database is 32returned in <b>countp</b>.</p> 33<p>When called on a database configured with secondary indices using the 34<a href="/api_c/db_associate.html">DB->associate</a> method, the DB->truncate method truncates the primary 35database and all secondary indices. A count of the records discarded 36from the primary database is returned.</p> 37<p>It is an error to call the DB->truncate method on a database with open 38cursors.</p> 39<p>The DB->truncate method 40returns a non-zero error value on failure 41and 0 on success. 42</p> 43<b>Parameters</b> <br> 44 <b>countp</b><ul compact><li>The <b>countp</b> parameter references memory into which 45 the number of records discarded from the database is copied.</ul> 46 <b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</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->truncate 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>EINVAL</b><ul compact><li>If there are open cursors in the database; or if an 70invalid flag value or parameter was specified.</ul> 71<br> 72<hr size=1 noshade> 73<br><b>Class</b> 74<a href="/api_c/db_class.html">DB</a> 75<br><b>See Also</b> 76<a href="/api_c/db_list.html">Databases and Related Methods</a> 77</tt> 78<table width="100%"><tr><td><br></td><td align=right> 79<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> 80</td></tr></table> 81<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 82</body> 83</html> 84
