CREATE TRIGGER BlockDelete ON Rezerwacja FOR Delete
AS
BEGIN
declare @Date date
declare @Paid bit
set @Date = (SELECT DataOd FROM deleted);
set @Paid = (SELECT Zaplacona FROM deleted);
if year(@Date) = 2015 or @Paid = 1
begin
	declare @ID int = (SELECT IdRezerwacja FROM deleted)
	print 'Rezerwacja o ID ' + @ID  + ' nie może zostać skasowana'
	rollback
end
END;