Re: Is there any different for foreign key to be serial instead of integer

On Wed, Jan 6, 2010 at 8:51 PM, Yan Cheng Cheok <yccheok@yahoo.com> wrote:
> I came across a lot of similar example for foreign key
>
> CREATE TABLE orderinfo
> (
> orderinfo_id serial ,
> customer_id integer NOT NULL,
> date_placed date NOT NULL,
> date_shipped date ,
> shipping numeric(7,2) ,
> CONSTRAINT orderinfo_pk PRIMARY KEY(orderinfo_id),
> CONSTRAINT orderinfo_customer_id_fk FOREIGN KEY(customer_id) REFERENCES
> customer(customer_id)
> );
>
> instead of let customer_id being type as integer, can i let it be serial? is there any difference?
>
> if the table referenced by customer_id is having primary key typed big serial, customer_id shall be declared as
bigint? 

serial and big serial are basically syntactic sugar for creating the
table with an int / bigint, create a sequence, create a default for
the bigint field, and setting a dependency in the system catalogs for
the sequence to the table.  So, yep, a serial / bigserial is
equivalent to int / bigint from an FK point of view.