DECLARE @return_value int;
EXEC @return_value = sys.sp_getapplock @Resource = N'SerialId:5104', @LockMode = 'Exclusive', @LockOwner = 'Session', @LockTimeout = 100;
IF @return_value > -1
BEGIN
PRINT N'Lock obtained';
END;
GO
/* do some work on SerialId 5104 here */
DECLARE @return_value int;
EXEC @return_value = sys.sp_releaseapplock @Resource = N'SerialId:5104', @LockOwner = 'Session';
IF @return_value = 0
BEGIN
PRINT N'Lock Released';