Re: DB design and foreign keys

[...unnecesary...]
> CREATE TABLE orders (
> id serial,
> order_code serial,
> customer_code integer REFERENCES customers (customer_code) NOT NULL,
> order_date time without time zone NOT NULL,
> remote_ip inet NOT NULL,
> order_time timestamp with time zone NOT NULL,
> order_type varchar(10) NOT NULL,
> state varchar(10) NOT NULL,
> PRIMARY KEY (id, order_code)
^^^^^^^^^^^^^^^^^^^
> );
[...unnecesary...]
>
> CREATE TABLE order_items (
> id serial,
> order_code integer REFERENCES orders (order_code) NOT NULL,
^^^^^^^^^^^^^^
[...unnecesary...]
> ERROR: there is no unique constraint matching given keys for referenced
> table "orders"

this is because the PK in the orders table has two fields not one...
so it founds no unique index on orders(order_code)

--
Atentamente,
Jaime Casanova
(DBA: DataBase Aniquilator ;)