Re: Alter table column constraint

So CREATE a table eg:
CREATE TABLE fks_for_tables
( fks_id serial
fks_values varchar(20),
CONSTRAINT fks_pkey PRIMARY KEY (fks_id),
CONSTRAINT fks-unique UNIQUE fks_values
)

Then
INSERT INTO fks_for_tables
(fks_values)
VALUES
( 'Agriculture'),
('Business'),
('other))',
'Chemicals')
...
...
('Transportation');

Then you can
ALTER TABLE your_table
ADD CONSTRAINT FOREIGN KEY (industry)
REFERENCES fks_for_tables(fks_valies);

On Mon, Dec 17, 2018 at 3:20 PM Rich Shepard <rshepard(at)appl-ecosys(dot)com>
wrote:

> On Mon, 17 Dec 2018, Melvin Davidson wrote:
>
> > Yes, you must drop then add the revised constraint. However, from your
> > statement above, it sounds to me as if you would be better off using A
> > FOREIGN kEY CONSTRAINT. It makes things a lot simpler.
>
> Melvin,
>
> I don't follow. Here's the DDL for that column:
>
> industry varchar(24) NOT NULL
> CONSTRAINT invalid_industry
> CHECK (industry in ('Agriculture', 'Business, other', 'Chemicals',
> 'Energy', 'Law', 'Manufacturing', 'Mining', 'Municipalities',
> 'Ports/Marine Services', 'Transportation')),
>
> and I want to remove Municipalities for the more general Government.
>
> Regards,
>
> Rich
>
>

--
*Melvin Davidson*
*Maj. Database & Exploration Specialist*
*Universe Exploration Command – UXC*
Employment by invitation only!