Hi, I have a table with a column of ID's (integer), these are unique except where they = -1 (column 1) I have a partial unique index where the value is not -1 to enforce this. I want to use this column as a foreign key on a column in another table (column 2), but cannot without a full unique index. Is there any way to add an equivalent constraint to a foreign key which restricts entries in column 2 to values in column 1? I tried a check where obs_id in (select id from ..), but subqueries are not supported in a check. I believe it is possible by using a table with nulls for the -1 values with a unique index on it as the foreign key, then a view which uses case or coalesce to present the nulls as -1, but this seems a cumbersome workaround. Thanks, Brent Wood Brent Wood DBA/GIS consultant NIWA, Wellington New Zealand NIWA is the trading name of the National Institute of Water & Atmospheric Research Ltd. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
