I just did something which seems to work alright and which makes sense to me now but which I have a funny feeling about. It may be good standard practice (and I just don't know about it) or dangerously foolish or just plain silly: I created a foreign key reference on a column that is also the primary key for this table as in create table institute ( id int4 references index ( id ) PRIMARY KEY, . . . and then used that column as a reference for a foreign key constraint in a couple of other tables: create table boss ( institute_id int4 references institute ( id ), . . . create table staff ( institute_id int4 references institute ( id ), . . . I am not really sure what happens when I delete or modify the id column in the table at the top of this "chain". Except for this uncertainty I don't think this scheme would pose a problem, but I may be wrong. Can anyone enlighten me? Ta, Frank
