Misa Simic wrote > I guess that rule can be achieved with triigers on TableA and TableC - but > the same is true for FK (and FK constraint is more effective then trigger > - > that is why I wonder would it be useful/achievable to create that kind of > constraint) > > Thoughts, ideas?
You create a common "keys in use" table and only insert a record into the main tables if you can successfully add the desired key to the shared keys table ( as a unique value ). Setup a normal FK to that table to help enforce that valid records must exist on the keys table. Not fool-proof but you only need to worry about insertions - delete from the pk table to remove the record from the main table and free up the key. David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/Not-In-Foreign-Key-Constraint-tp5771056p5771546.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
