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<title>Berkeley DB Reference Guide: Access Methods</title>
<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
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<h3>Berkeley DB Reference Guide: Access Methods</h3>
<p>
<h1 align=center>Retrieving records with a cursor</h1>
<p>
The <a href="../../api_c/Dbc/get.html">DBcursor->c_get</a> function is the standard function for retrieving
records from the database, with a cursor. In general, the cursor get
function takes a key and returns the associated data from the database.
<p>
There are several flags that you can set to customize retrieval:
<dl compact>
<p><dt><a href="../../api_c/Dbc/get.html#DB_FIRST">DB_FIRST</a><dd>Return the first record from the database.
<p><dt><a href="../../api_c/Dbc/get.html#DB_LAST">DB_LAST</a><dd>Return the last record from the database.
<p><dt><a href="../../api_c/Dbc/get.html#DB_NEXT">DB_NEXT</a><dd>Return the record from the database immediately following the cursor.
<p><dt><a href="../../api_c/Dbc/get.html#DB_NEXT_DUP">DB_NEXT_DUP</a><dd>Return the record from the database immediately following the cursor, if
it is a duplicate data item for the current key.
<p><dt><a href="../../api_c/Dbc/get.html#DB_PREV">DB_PREV</a><dd>Return the record from the database immediately preceding the cursor.
<p><dt><a href="../../api_c/Dbc/get.html#DB_CURRENT">DB_CURRENT</a><dd>Return the record from the database currently pointed to by the cursor.
<p><dt><a href="../../api_c/Dbc/get.html#DB_SET">DB_SET</a><dd>Return the record from the database that matches the supplied key.
<p><dt><a href="../../api_c/Dbc/get.html#DB_SET_RANGE">DB_SET_RANGE</a><dd>Return the smallest record in the database greater than or equal to the
supplied key. This functionality permits partial key matches and range
searches.
<p><dt><a href="../../api_c/Db/get.html#DB_GET_BOTH">DB_GET_BOTH</a><dd>Return the record from the database that matches both the supplied key
and data items. This is particularly useful when there are large numbers
of duplicate records for a key, as it allows the cursor to easily be
positioned at the correct place for traversal of some part of a large set
of duplicate records.
<p><dt><a href="../../api_c/Db/get.html#DB_SET_RECNO">DB_SET_RECNO</a><dd>If the underlying database is a Btree, and was configured so that it is
possible to search it by logical record number, retrieve a specific
record.
<p><dt><a href="../../api_c/Dbc/get.html#DB_GET_RECNO">DB_GET_RECNO</a><dd>If the underlying database is a Btree, and was configured so that it is
possible to search it by logical record number, return the record number
for the current cursor record.
<p><dt><a href="../../api_c/Dbc/get.html#DB_RMW">DB_RMW</a><dd>Acquire write locks instead of read locks during retrieval. This can
enhance performance in threaded applications where deadlock is a
concern.
</dl>
<p>
In all cases, the cursor is repositioned by a <a href="../../api_c/Dbc/get.html">DBcursor->c_get</a> operation
to point to the newly returned key/data pair in the database.
<p>
<a href="../../ref/am/cursor.html"><img src="../../images/prev.gif"></a>
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