-- [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 numeric not null , type valves_type not null , setting numeric not null , minor_loss numeric not null );