Hi, Imagine I have two tables, like this: create table bla_a ( id serial primary key, name varchar(31) not null, comment varchar(31) ); create table bla_b ( id serial primary key, name varchar(31) not null, blabla int ); I want to make sure that both tables could not have the same value for name column. Can I do that? insert into bla_a ( id, name, comment ) values ( 1, 'bo', 'ha'); insert into bla_b ( id, name, comment ) values ( 1, 'bo', 3); I want to make the second insertion failed because of unique constraint. Can I do that?