Referrential Integrity Question

What is the best approach to insure referrential integrity at the server, between two tables when: - The parent table (tab1) has a primary key on (col1,col2), and contains many rows with duplicates in col1 - The child table (tab2) contains (col1) values with a contraint before an insert or update (i.e. tab2.col1 values must exist in tab1.col1) FWIW: Running under OnLine DSA 7.10 I'm posting this for someone I work with, and would appreciate responses emailed to me a following address. ================================================================== Jon Vemo Internet: jvemo@cyberspace.com Bothell, WA USA ------------------------------------------------------------------ Watch out for road-kill on the information superhighway....SPLAT!! ==================================================================