-- [VALVES] create type valves_type as enum ('PRV', 'PSV', 'PBV', 'FCV', 'TCV', 'GPV'); create table valves ( id varchar(32) primary key references _link(id) , node1 varchar(32) references _node(id) not null , node2 varchar(32) references _node(id) not null , diameter float8 not null , type valves_type not null , setting text not null , minor_loss float8 not null ); -- delete when delete node1 -- delete when delete node2