Check Constraints

I have a table describing employees.
I want to make sure that those employees who earn commission (commission is not null) earn more than 0%

I issued following command:

ALTER TABLE EMP
ADD CONSTRAINT
check (COMMISSION > 0)

Oracle returned an error:
ORA-02438 Column check constraint cannot reference other columns

I decided to name this CONSTRAINT

ALTER TABLE EMP
ADD CONSTRAINT check_comm
CHECK (COMMISSION > 0) And everything went alright.
What's the explanation for the strange error? Received on Fri Jan 21 2005 - 08:19:39 CST