Question

Is it possible to add data integrity between columns in different tables in SQL Server?
I have table Pay with column Date and table Orders with column DateofOrder. And I would like to add the data integrity so the Date cannot be earlier than the DateofOrder.
And when the user insert there the same date or even earlier database would show error.

Answer 1

I think you mean something like this, here done with a trigger;

CREATE TRIGGER trig_pay ON Pay
FOR INSERT, UPDATE
AS
IF EXISTS(SELECT * 
        FROM [Order] o
        JOIN inserted i
        ON o.id = i.payment_id
        WHERE DateOfOrder>[date])
BEGIN
  RAISERROR ('Sorry, Dave', 16, 1)
  ROLLBACK;
  RETURN;
END

INSERT INTO [Order] values (1, GETDATE());               -- Order today
INSERT INTO Pay values (1, DATEADD(dd, -1, getdate()));  -- Pay yesterday
> Sorry, Dave