Happy New Year all, My readings taught me that standard SQL has a domain constraint that checks for the same valid characters in a column common to multiple tables. Example: CREATE DOMAIN state_code AS char(2) DEFAULT '??' CONSTRAINT valid_state_code CHECK (value IN ('AL', 'AK', 'AZ', ...)); This applies to all tables each having a column named state_code. I see the value of this feature when multiple tables have start_date and end_date columns with a constraint that ensures the start_date is <= to the end date. Reading the release 10 manual I find many constraints and I want to learn which one will implement this feature. A pointer is needed. Rich