mysql_data_seek to reset mysql recordset in php

Posted on February 13, 2009 by dreamluverz

I’ve been into this situation where I need to reset the recordset for mysql and one way to do this is by using mysql_data_seek().

Sample below from mysql site:

Description





bool mysql_data_seek ( resource result, int row_number )





mysql_data_seek() moves the internal row pointer of the MySQL result associated with the specified result identifier to point to the specified row number. The next call to a MySQL fetch function, such as mysql_fetch_assoc(), would return that row.

row_number starts at 0. The row_number should be a value in the range from 0 to mysql_num_rows() – 1. However if the result set is empty (mysql_num_rows() == 0), a seek to 0 will fail with a E_WARNING and mysql_data_seek() will return FALSE.

Parameters

result
The result resource that is being evaluated. This result comes from a call to mysql_query().

row_number
The desired row number of the new result pointer.

Return Values

Returns TRUE on success or FALSE on failure.

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$db_selected = mysql_select_db('sample_db');
if (!$db_selected) {
die('Could not select database: ' . mysql_error());
}
$query = 'SELECT last_name, first_name FROM friends';
$result = mysql_query($query);
if (!$result) {
die('Query failed: ' . mysql_error());
}
/* fetch rows in reverse order */
for ($i = mysql_num_rows($result) - 1; $i >= 0; $i--) {
if (!mysql_data_seek($result, $i)) {
echo "Cannot seek to row $i: " . mysql_error() . "\n";
continue;
}

if (!($row = mysql_fetch_assoc($result))) {
continue;
}

echo $row['last_name'] . ' ' . $row['first_name'] . "<br />\n";
}

mysql_free_result($result);
?>

Notes

Note: The function mysql_data_seek() can be used in conjunction only with mysql_query(), not with mysql_unbuffered_query().

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