Re: DB design and foreign keys

Jaime Casanova wrote:

> [...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)
>
>
>
then, what would you suggest, to remove the primary key from the 'id'
column? or to remove the 'id' column at all?

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

thank you for your response, regards,
Gianluca Riccardi