checking dates with triggers or constraints

Hi,

I have a table that contains various data with a start and end date. When a user enters the information I need to check that the end date is older than the start date.

What is the easiest way to do this - using a trigger?

And is the code below correct ?

CREATE TRIGGER checkdate
ON Prodn_Problem
FOR INSERT,UPDATE
AS
DECLARE @.start_date datetime
SELECT @.start_date = (SELECT startdate FROM inserted)
DECLARE @.end_date datetime
SELECT @.end_date = (SELECT enddate FROM inserted)
BEGIN
IF(@.end_date < @.start_date)
ROLLBACK
END

Thanks.By using a trigger, you check the data when it's already inserted or updated in the table. When you use a check constraint you can verify before the information is entered. Another method is to create a stored procedure which does the checking an let you users enter information through this stored procedure.