How to: Disable Multiple Active Resultsets (MARS)

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If you need to connect to a SQL Server data source that does not enable Multiple Active Result Sets (MARS), you can use the MultipleActiveResultSets connection option to disable or enable MARS.

Procedure

To disable MARS support

• Use the following connection option:

  'MultipleActiveResultSets'=>false  
  

  If your application attempts to execute a query on a connection that has an open active result set, the second query attempt will return the following error information:

  The connection cannot process this operation because there is a statement with pending results. To make the connection available for other queries either fetch all results, cancel or free the statement. For more information about the MultipleActiveResultSets connection option, see Connection Options.

SQLSRV example

The following example shows how to disable MARS support, using the SQLSRV driver of the Microsoft Drivers for PHP for SQL Server.

<?php  
/* Connect to the local server using Windows Authentication and  
specify the AdventureWorks database as the database in use. */  
$serverName = "MyServer";  
$connectionInfo = array( "Database"=>"AdventureWorks", 'MultipleActiveResultSets'=> false);  
$conn = sqlsrv_connect( $serverName, $connectionInfo);  
if( $conn === false )  
{  
   echo "Could not connect.\n";  
   die( print_r( sqlsrv_errors(), true));  
}  
  
sqlsrv_close( $conn);  
?>  

PDO_SQLSRV example

The following example shows how to disable MARS support, using the PDO_SQLSRV driver of the Microsoft Drivers for PHP for SQL Server.

<?php  
// Connect to the local server using Windows Authentication and AdventureWorks database  
$serverName = "(local)";   
$database = "AdventureWorks";  
  
try {  
   $conn = new PDO(" sqlsrv:server=$serverName ; Database=$database ; MultipleActiveResultSets=false ", NULL, NULL);   
   $conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );   
}  
  
catch( PDOException $e ) {  
   die( "Error connecting to SQL Server" );   
}  
  
$conn = null;   
?>  

See Also

Connecting to the Server