> 1. I have a table with mailmessages, which has an FK to a table of hub users. > 2. I'd like to retain the content of message repository (with it's domain key not cleared), when I drop a particular username from service .... to release that username to others. > 3. I try to do that with FK "on-update/on-delete" actions, but to no avail: Interesting discussion on database theory! If you switched to surrogate keys for all your tables, you could soft-delete accounts with a deleted_at column, and then have a unique index on username+domain (or username+domain_id?) that is WHERE deleted_at IS NULL. Does that work? Probably you want the same approach for the maildomains table to enforce unique non-deleted domains. It seems like if you want to retain data for auditing, you don't really want to delete *anything*, including the username. Surrogate keys and a partial unique index would let you do that I believe. Paul -- _________________________________ Pulchritudo splendor veritatis. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
