Re: Referential Integrity

On Wed, 13 May 1998, Mike Lemler wrote:

> I haven't been able to find documentation on how to implement referential
> integrity between tables with postgres via sql. Could someone please post
> an example. Thanks.
>
> Michael.
>
Table Constraint definition:

[ CONSTRAINT name ]
{ PRIMARY KEY constraint |
UNIQUE constraint |
CHECK constraint }

Column Constraint definition:

[ CONSTRAINT name ]
{ NOT NULL constraint |
PRIMARY KEY constraint |
UNIQUE constraint |
CHECK constraint }

examples:

--defines a CHECK column constraint:
--
CREATE TABLE distributors (
did DECIMAL(3) CHECK (did > 100),
name VARCHAR(40)
);

--defines a CHECK table constraint:
--
CREATE TABLE distributors (
did DECIMAL(3),
name VARCHAR(40)
CONSTRAINT con1 CHECK (did > 100 AND name > '')
);

PS: FOREIGN KEY is not implemented yet you can use TRIGGERS instead
take a look at ...contrib/refint*
Jose'