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Cursor Types (PDO_SQLSRV Driver)

SQL Server 2008 R2

The PDO_SQLSRV driver lets you create scrollable result sets with one of several cursors.

For information on how to specify a cursor using the PDO_SQLSRV driver, and for code samples, see PDO::prepare.

Prior to version 3.0 of the Microsoft Drivers for PHP for SQL Server, the PDO_SQLSRV driver allowed you to create a result set with a server-side forward-only or static cursor. Beginning in version 3.0 of the Microsoft Drivers for PHP for SQL Server, keyset and dynamic cursors are also available.

You can indicate the type of server-side cursor by using PDO::prepare or PDOStatement::setAttribute to select either cursor type:

  • PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY

  • PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL

You can request a keyset or dynamic cursor by specifying PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL and then pass the appropriate value to PDO::SQLSRV_ATTR_CURSOR_SCROLL_TYPE. Possible values that you can pass to PDO::SQLSRV_ATTR_CURSOR_SCROLL_TYPE are:

  • PDO::SQLSRV_CURSOR_BUFFERED

  • PDO::SQLSRV_CURSOR_DYNAMIC

  • PDO::SQLSRV_CURSOR_KEYSET_DRIVEN

  • PDO::SQLSRV_CURSOR_STATIC

Client-side cursors were added in version 3.0 of the Microsoft Drivers for PHP for SQL Server that allows you to cache an entire result set in memory. One advantage is that row count is available after a query is executed.

Client-side cursors should be used for small- to medium-sized result sets. Large result sets should use server-side cursors.

A query will return false if the buffer is not large enough to hold an entire result set when using a client-side cursor. You can increase the buffer size up to the PHP memory limit.

You can configure the size of the buffer that holds the result set with the PDO::SQLSRV_ATTR_CLIENT_BUFFER_MAX_KB_SIZE attribute of PDO::setAttribute or PDOStatement::setAttribute. You can also set the maximum buffer size in the php.ini file with pdo_sqlsrv.client_buffer_max_kb_size (for example, pdo_sqlsrv.client_buffer_max_kb_size = 1024).

You indicate that you want a client-side cursor by using PDO::prepare or PDOStatement::setAttribute and select the PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL cursor type. You then specify PDO::SQLSRV_ATTR_CURSOR_SCROLL_TYPE => PDO::SQLSRV_CURSOR_BUFFERED.

<?php
$database = "AdventureWorks";
$server = "(local)";
$conn = new PDO( "sqlsrv:server=$server ; Database = $database", "", "");

$query = "select * from Person.ContactType";
$stmt = $conn->prepare( $query, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL, PDO::SQLSRV_ATTR_CURSOR_SCROLL_TYPE => PDO::SQLSRV_CURSOR_BUFFERED));
$stmt->execute();
print $stmt->rowCount();

echo "\n";

while ( $row = $stmt->fetch( PDO::FETCH_ASSOC ) ){
   print "$row[Name]\n";
}
echo "\n..\n";

$row = $stmt->fetch( PDO::FETCH_BOTH, PDO::FETCH_ORI_FIRST );
print_r($row);

$row = $stmt->fetch( PDO::FETCH_ASSOC, PDO::FETCH_ORI_REL, 1 );
print "$row[Name]\n";

$row = $stmt->fetch( PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT );
print "$row[1]\n";

$row = $stmt->fetch( PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR );
print "$row[1]..\n";

$row = $stmt->fetch( PDO::FETCH_NUM, PDO::FETCH_ORI_ABS, 0 );
print_r($row);

$row = $stmt->fetch( PDO::FETCH_NUM, PDO::FETCH_ORI_LAST );
print_r($row);
?>

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