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DBT: Bulk Retrieval
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If either of the <a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE">DB_MULTIPLE</a> or <a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flags
were specified to the <a href="../../db4-devel-4.7.25/api_c/db_get.html">DB-&gt;get</a> or <a href="../../db4-devel-4.7.25/api_c/dbc_get.html">DBcursor-&gt;get</a> methods, the data
<a href="../../db4-devel-4.7.25/api_c/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:
 
<a name="DB_MULTIPLE_INIT">DB_MULTIPLE_INIT</a><ul compact><li><pre>DB_MULTIPLE_INIT(void *pointer, <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> *data);</pre>
Initialize the retrieval. The pointer parameter is a variable
to be initialized. The data parameter is a <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a>
structure returned from a successful call to <a href="../../db4-devel-4.7.25/api_c/db_get.html">DB-&gt;get</a> or
<a href="../../db4-devel-4.7.25/api_c/dbc_get.html">DBcursor-&gt;get</a> for which one of the <a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE">DB_MULTIPLE</a> or
<a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flags was specified.</ul>
<a name="DB_MULTIPLE_NEXT">DB_MULTIPLE_NEXT</a><ul compact><li><pre>DB_MULTIPLE_NEXT(void *pointer, <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> *data, void *retdata, size_t retdlen);</pre>
The data parameter is a <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> structure returned from a
successful call to <a href="../../db4-devel-4.7.25/api_c/db_get.html">DB-&gt;get</a> or <a href="../../db4-devel-4.7.25/api_c/dbc_get.html">DBcursor-&gt;get</a> for which the
<a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE">DB_MULTIPLE</a> flag was specified. The pointer and
data parameters must have been previously initialized by a call
to DB_MULTIPLE_INIT. The retdata parameter is set to
refer to the next data element in the returned set, and the
retdlen parameter is set to the length, in bytes, of that data
element. When used with the Queue and Recno access methods,
retdata will be set to NULL for deleted records. The
pointer parameter is set to NULL if there are no more data
elements in the returned set.</ul>
<a name="DB_MULTIPLE_KEY_NEXT">DB_MULTIPLE_KEY_NEXT</a><ul compact><li><pre>DB_MULTIPLE_KEY_NEXT(void *pointer, <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> *data,
	void *retkey, size_t retklen, void *retdata, size_t retdlen);</pre>
The data parameter is a <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> structure returned from a
successful call to <a href="../../db4-devel-4.7.25/api_c/dbc_get.html">DBcursor-&gt;get</a> with the Btree or Hash access methods
for which the <a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flag was specified. The
pointer and data parameters must have been previously
initialized by a call to DB_MULTIPLE_INIT. The retkey
parameter is set to refer to the next key element in the returned set,
and the retklen parameter is set to the length, in bytes, of
that key element. The retdata parameter is set to refer to the
next data element in the returned set, and the retdlen parameter
is set to the length, in bytes, of that data element. The
pointer parameter is set to NULL if there are no more key/data
pairs in the returned set.</ul>
<a name="DB_MULTIPLE_RECNO_NEXT">DB_MULTIPLE_RECNO_NEXT</a><ul compact><li><pre>DB_MULTIPLE_RECNO_NEXT(void *pointer, <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> *data,
	db_recno_t recno, void * retdata, size_t retdlen);</pre>
The data parameter is a <a href="../../db4-devel-4.7.25/api_c/dbt_class.html">DBT</a> structure returned from a
successful call to <a href="../../db4-devel-4.7.25/api_c/dbc_get.html">DBcursor-&gt;get</a> with the Queue or Recno access
methods for which the <a href="../../db4-devel-4.7.25/api_c/dbc_get.html#DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a> flag was specified. The
pointer and data parameters must have been previously
initialized by a call to DB_MULTIPLE_INIT. The recno
parameter is set to the record number of the next record in the returned
set. The retdata parameter is set to refer to the next data
element in the returned set, and the retdlen parameter is set to
the length, in bytes, of that data element. Deleted records are not
included in the results. The pointer parameter is set to NULL
if there are no more key/data pairs in the returned set.</ul>
 
These macros may be called multiple times, but DB_MULTIPLE_INIT
must be called before each new access of the data.
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