Check constraint

I have a column that must = 1 or 0. SO I want to add a constraint

CHECK (Flag IN (1,2)).

1. Does that exclude NULLs?
2. Are there any differences, speed or otherwise between CHECK (Flag IN (1,2)). and CHECK ((Flag = 1) OR (Flag = 2)). I'm assuming it would be negligable, but I'm curious.

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I have two columns, and for legacy purposes they must work with each other.

If Flag = 1, The_Date must be null
If Flag = 0, The_Date nmust not be null

I've added two constraints to check this

The_Date_NOT_NULL CHECK ( NOT ((Flag = 0) AND (The_Date IS NULL))

The_Date_NULL CHECK ( NOT ((Flag = 1) AND (The_Date IS NOT NULL))

I though an exclusive or would be better, but I could not find such an operator for PL/SQL. Is there one?

Brian Received on Fri Oct 13 2000 - 10:51:44 CDT