FW: FOREIGN KEY syntax

FYI

> -----Original Message-----
> From: Andrzej Mazurkiewicz
> Sent: 3 marca 2000 17:05
> To: 'Ron Peterson'
> Cc: pgsql-general(at)postgreSQL(dot)org
> Subject: RE: [GENERAL] FOREIGN KEY syntax
>
>
>
> -----Original Message-----
> From: Ron Peterson [SMTP:rpeterson(at)yellowbank(dot)com]
> Sent: 3 marca 2000 15:55
> To: Andrzej Mazurkiewicz
> Cc: pgsql-general(at)postgreSQL(dot)org
> Subject: Re: [GENERAL] FOREIGN KEY syntax
>
> Andrzej Mazurkiewicz wrote:
> >
> > The following information is based on gram.y file of postgres sources
> >
> > FOREIGN KEY ( columnList ) REFERENCES tableName [ ( columnList) ] [MATCH
> > FULL] [ON DELETE action] [ON UPDATE action]
> >
> > [[NOT] DEFERRABLE] [INITIALLLY {IMMEDIATE | DEFERRED}] (not all matches
> are
> > allowed)
> >
> > "action" is {NO ACTION | RESTRICT | CASCADE | SET NULL_P | SET DEFAULT
> }
>
> What does action RESTRICT do? Disallow the update or delete?
> [Andrzej Mazurkiewicz] Disallows to delete master table row if there are
> detail records in FOREIGN KEY relation. Disallows to modify referenced
> columns in master row it there is at least one detail row in FOREIGN KEY
> relation with that master row.
>
> And what is MATCH FULL?
> [Andrzej Mazurkiewicz] I would not like to speculate perhaps somebody else
> knows exact answer.
>
> I take it that the 'List' in 'columList' implies that a foreign key can
> span multiple columns?
> [Andrzej Mazurkiewicz] YES. my understanding is that the second column
> list means not only primary key can be referenced but any other
> combination of columns as far as it is unique in the master table..
>
> I did sucessfully create some tables with foreign keys using CREATE
> TABLE and ALTER TABLE. That's as far as I've gotten yet, though. Maybe
> when I get some various working examples I'll post them back. Here's
> one example (in case anyone's interested):
>
> CREATE TABLE contact (
> contact_id SERIAL
> PRIMARY KEY,
> name_sort varchar(80),
> name_print varchar(80),
> created timestamp default current_timestamp,
> FOREIGN KEY (address_id)
> REFERENCES address(address_id)
> ON DELETE CASCADE
> );
>
> Thanks for help.
>
> Ron Peterson
> rpeterson(at)yellowbank(dot)com