DECLARE
	sWhere VARCHAR2( 500 ) := null;
	
BEGIN
	sWhere := 'tafel_id <> ( SELECT res.tafel_id FROM reservaties res 
              WHERE res.datum = :global.datum )          	
              AND rokers = :global.roken_check_box
              AND maxpers >= :global.aantalpers'; 
              
	set_block_property( 'taf', DEFAULT_WHERE, sWhere );  
	Execute_Query;
	
IF NOT Form_Success THEN
	sWhere := 'rokers = :global.roken_check_box
       AND maxpers >= :global.aantalpers';            

	set_block_property( 'taf', DEFAULT_WHERE, sWhere );  
	Execute_Query;
	raise form_trigger_failure;
END IF;  

END;