Adding Serial Type

[David Pratt <fairwinds@xxxxxxxxxxx>]

Pretty basic question. Is it necessary to add NOT NULL or UNIQUE NOT 
NULL to SERIAL or is this implicit and unnecessary?

ie.

CREATE TABLE new_table (
	id                             SERIAL UNIQUE NOT NULL,
	description             TEXT NOT NULL
);

Or should I just use below because Serial type implies this.

CREATE TABLE new_table (
	id                             SERIAL,
	description             TEXT NOT NULL
);


Regards,
David