Is This s bug: create table A ( key varchar(20) not null primary key ); create table B ( id serial not null primary key, col1 varchar(20) not null, col2 varchar(20) not null ); alter table B create constraint fk_col1 foreign key ( col1 ) references A ( key ) on delete cascade on update cascade; alter table B create constraint fk_col2 foreign key ( col2 ) references A ( key ) on delete cascade on update cascade; SQL Creation and operation works fine. In the case that one row in table B where col1 = col2, if I update A.key, I'll get a referential integrity violation?? ie: ERROR: fk_col1 referential integrity violation - key referenced from B not found in A. Is there a way to make this type of constraint work with the update? If not, is there a way to create a constraint so that col1 != col2 is inforced? Thanks in advance.. Dennis ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]