Re: simulate multiple primary keys

In response to Brandon Metcalf <brandon(at)geronimoalloys(dot)com>:

> I have the following table:
>
> gms=> \d jobclock
> Table "public.jobclock"
> Column | Type | Modifiers
> -------------+--------------------------------+----------------------------------------------------------------
> jobclock_id | integer | not null default nextval('jobclock_jobclock_id_seq'::regclass)
> employee_id | integer | not null
> machine_id | character varying(4) | not null
> workorder | character varying(8) | not null
> operation | integer | not null
> bartype | character varying(10) | not null
> clockin | timestamp(0) without time zone | not null
> clockout | timestamp(0) without time zone | default NULL::timestamp without time zone
> comments | character varying(255) | default NULL::character varying
> Indexes:
> "jobclock_pkey" PRIMARY KEY, btree (jobclock_id)
> ...
>
> I need to keep jobclock_id unique and not null, but I also need to
> ensure that no row is duplicated. Is my best bet to drop the current
> primary key and make a primary key out of the columns that I want to
> ensure remain unique from row to row?

Your primary key can span multiple columns, i.e.
PRIMARY KEY(jobclock_id, employee_id, machine_id)
Could be more columns.

Keep in mind that this ensures that the combination of all those
columns is unique, which may or may not be what you want.

--
Bill Moran
http://www.potentialtech.com
http://people.collaborativefusion.com/~wmoran/