-- [PIPES] create type pipes_status as enum ('OPEN', 'CLOSED', 'CV'); create table pipes ( id varchar(32) primary key references _link(id) , node1 varchar(32) references _node(id) not null , node2 varchar(32) references _node(id) not null , length numeric not null , diameter numeric not null , roughness numeric not null , minor_loss numeric not null , status pipes_status not null , check (node1 <> node2) ); -- delete when delete node1 -- delete when delete node2