<!--$Id: dbt_bulk.html,v 1.1.1.1 2003/02/15 04:55:48 zarzycki Exp $--> <!--Copyright 1997-2002 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DBT</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> <a name="2"><!--meow--></a> <table width="100%"><tr valign=top> <td> <h1>DBT: Bulk Retrieval</h1> </td> <td align=right> <a href="../api_cxx/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <hr size=1 noshade> <tt> <a name="3"><!--meow--></a> <p>If either of the <a href="../api_cxx/dbc_get.html#DB_MULTIPLE">DB_MULTIPLE</a> or <a href="../api_cxx/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flags were specified to the <a href="../api_cxx/db_get.html">Db::get</a> or <a href="../api_cxx/dbc_get.html">Dbc::get</a> methods, the data <a href="../api_cxx/dbt_class.html">Dbt</a> returned by those interfaces will refer to a buffer that is filled with data. Access to that data is through the following macros: <p><dl compact> <p><dt><a name="DB_MULTIPLE_INIT">DB_MULTIPLE_INIT</a><dd><pre>DB_MULTIPLE_INIT(void *pointer, <a href="../api_cxx/dbt_class.html">Dbt</a> *data);</pre> <p>Initialize the retrieval. The <b>pointer</b> argument is a variable to be initialized. The <b>data</b> argument is a <a href="../api_cxx/dbt_class.html">Dbt</a> structure returned from a successful call to <a href="../api_cxx/db_get.html">Db::get</a> or <a href="../api_cxx/dbc_get.html">Dbc::get</a> for which one of the <a href="../api_cxx/dbc_get.html#DB_MULTIPLE">DB_MULTIPLE</a> or <a href="../api_cxx/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flags was specified. <p><dt><a name="DB_MULTIPLE_NEXT">DB_MULTIPLE_NEXT</a><dd><pre>DB_MULTIPLE_NEXT(void *pointer, <a href="../api_cxx/dbt_class.html">Dbt</a> *data, void *retdata, size_t retdlen);</pre> <p>The <b>data</b> argument is a <a href="../api_cxx/dbt_class.html">Dbt</a> structure returned from a successful call to <a href="../api_cxx/db_get.html">Db::get</a> or <a href="../api_cxx/dbc_get.html">Dbc::get</a> for which the <a href="../api_cxx/dbc_get.html#DB_MULTIPLE">DB_MULTIPLE</a> flag was specified. The <b>pointer</b> and <b>data</b> arguments must have been previously initialized by a call to DB_MULTIPLE_INIT. The <b>retdata</b> argument is set to refer to the next data element in the returned set, and the <b>retdlen</b> argument is set to the length, in bytes, of that data element. When used with the Queue and Recno access methods, <b>retdata</b> will be set to NULL for deleted records. The <b>pointer</b> argument is set to NULL if there are no more data elements in the returned set. <p><dt><a name="DB_MULTIPLE_KEY_NEXT">DB_MULTIPLE_KEY_NEXT</a><dd><pre>DB_MULTIPLE_KEY_NEXT(void *pointer, <a href="../api_cxx/dbt_class.html">Dbt</a> *data, void *retkey, size_t retklen, void *retdata, size_t retdlen);</pre> <p>The <b>data</b> argument is a <a href="../api_cxx/dbt_class.html">Dbt</a> structure returned from a successful call to <a href="../api_cxx/db_get.html">Db::get</a> or <a href="../api_cxx/dbc_get.html">Dbc::get</a> for which the <a href="../api_cxx/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flag was specified. The <b>pointer</b> and <b>data</b> arguments must have been previously initialized by a call to DB_MULTIPLE_INIT. The <b>retkey</b> argument is set to refer to the next key element in the returned set, and the <b>retklen</b> argument is set to the length, in bytes, of that key element. The <b>retdata</b> argument is set to refer to the next data element in the returned set, and the <b>retdlen</b> argument is set to the length, in bytes, of that data element. The <b>pointer</b> argument is set to NULL if there are no more key/data pairs in the returned set. <p><dt><a name="DB_MULTIPLE_RECNO_NEXT">DB_MULTIPLE_RECNO_NEXT</a><dd><pre>DB_MULTIPLE_RECNO_NEXT(void *pointer, <a href="../api_cxx/dbt_class.html">Dbt</a> *data, db_recno_t recno, void * retdata, size_t retdlen);</pre> <p>The <b>data</b> argument is a <a href="../api_cxx/dbt_class.html">Dbt</a> structure returned from a successful call to <a href="../api_cxx/db_get.html">Db::get</a> or <a href="../api_cxx/dbc_get.html">Dbc::get</a> for which the <a href="../api_cxx/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flag was specified. The <b>pointer</b> and <b>data</b> arguments must have been previously initialized by a call to DB_MULTIPLE_INIT. The <b>recno</b> argument is set to the record number of the next record in the returned set. The <b>retdata</b> argument is set to refer to the next data element in the returned set, and the <b>retdlen</b> argument is set to the length, in bytes, of that data element. When used with the Queue and Recno access methods, <b>retdata</b> will be set to NULL for deleted records. The <b>pointer</b> argument is set to NULL if there are no more key/data pairs in the returned set. </dl> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_cxx/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> </body> </html>