On 11 June 2022 08:05:41 Rino Mardo <rino1...@gmail.com> wrote:
hello!
really noob question here. i have this experimental database design:
create table products (
product_id serial primary key,
description text,
supplier_id????) ;
create table supplier (
supplier_id serial primary key,
description text) ;
the products table should be linked to the supplier table via "supplier_id"
column. i can't find out what would be the data type of supplier_id in
table products to do that. i tried
Hi there,
"serial" isn't a real type - it's just a shortcut for "integer not null
default nextval(....)". Read about it here:
https://www.postgresql.org/docs/current/datatype-numeric.html#DATATYPE-SERIAL
So the supplier_id column in the first table should be of type "integer".
supplier_id serial primary key references supplier
but it won't allow multiple primary key.
how then to proceed?
You need a foreign key.... add this to the first table:
constraint <constraint name> foreign key (supplier_id) references
supplier(supplier_id)
I hope this helps.
Ray.
regards,
