<!--$Id: put.html,v 1.1.1.1 2003/02/15 04:56:03 zarzycki Exp $--> <!--Copyright 1997-2002 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB Reference Guide: Release 3.1: DB->put</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,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><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></h3></td> <td align=right><a href="../../ref/upgrade.3.1/set_paniccall.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../reftoc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/upgrade.3.1/dup.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p> <h1 align=center>Release 3.1: DB->put</h1> <p>For the Queue and Recno access methods, when the <a href="../../api_c/db_put.html#DB_APPEND">DB_APPEND</a> flag is specified to the <a href="../../api_c/db_put.html">DB->put</a> interface, the allocated record number is returned to the application in the <b>key</b> <a href="../../api_c/dbt_class.html">DBT</a> argument. In previous releases of Berkeley DB, this <a href="../../api_c/dbt_class.html">DBT</a> structure did not follow the usual <a href="../../api_c/dbt_class.html">DBT</a> conventions. For example, it was not possible to cause Berkeley DB to allocate space for the returned record number. Rather, it was always assumed that the <b>data</b> field of the <b>key</b> structure referred to memory that could be used as storage for a db_recno_t type. <p>As of the Berkeley DB 3.1.0 release, the <b>key</b> structure behaves as described in the <a href="../../api_c/dbt_class.html">DBT</a> C++/Java class or C structure documentation. <p>Applications which are using the <a href="../../api_c/db_put.html#DB_APPEND">DB_APPEND</a> flag for Queue and Recno access method databases will require a change to upgrade to the Berkeley DB 3.1 releases. The simplest change is likely to be to add the <a href="../../api_c/dbt_class.html#DB_DBT_USERMEM">DB_DBT_USERMEM</a> flag to the <b>key</b> structure. For example, code that appears as follows: <p><blockquote><pre>DBT key; db_recno_t recno; <p> memset(&key, 0, sizeof(DBT)); key.data = &recno; key.size = sizeof(recno); DB->put(DB, NULL, &key, &data, DB_APPEND); printf("new record number is %lu\n", (u_long)recno);</pre></blockquote> <p>would be changed to: <p><blockquote><pre>DBT key; db_recno_t recno; <p> memset(&key, 0, sizeof(DBT)); key.data = &recno; key.ulen = sizeof(recno); key.flags = DB_DBT_USERMEM; DB->put(DB, NULL, &key, &data, DB_APPEND); printf("new record number is %lu\n", (u_long)recno);</pre></blockquote> <p>Note that the <b>ulen</b> field is now set as well as the flag value. An alternative change would be: <p><blockquote><pre>DBT key; db_recno_t recno; <p> memset(&key, 0, sizeof(DBT)); DB->put(DB, NULL, &key, &data, DB_APPEND); recno = *(db_recno_t *)key->data; printf("new record number is %lu\n", (u_long)recno);</pre></blockquote> <table width="100%"><tr><td><br></td><td align=right><a href="../../ref/upgrade.3.1/set_paniccall.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../reftoc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/upgrade.3.1/dup.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> </body> </html>