Paul,
----- Original Message -----
From: "Paul DuBois" <[EMAIL PROTECTED]>
To: "Heikki Tuuri" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Monday, March 17, 2003 1:05 AM
Subject: Re: Foreign Key and default action/RESTRICT behaviour?
> At 23:12 +0200 3/16/03, Heikki Tuuri wrote:
> >Tor,
> >
> >----- Original Message -----
> >From: ""Tor R. Skoglund (NextG)"" <[EMAIL PROTECTED]>
> >Newsgroups: mailing.database.mysql
> >Sent: Sunday, March 16, 2003 10:11 PM
> >Subject: Foreign Key and default action/RESTRICT behaviour?
> >
> > > Hi List, regarding the foreign key definitions:
> >>
> >> [CONSTRAINT symbol] FOREIGN KEY (index_col_name, ...)
> >> REFERENCES table_name (index_col_name, ...)
> >> [ON DELETE {CASCADE | SET NULL | NO ACTION
> >> | RESTRICT}]
> >> [ON UPDATE {CASCADE | SET NULL | NO ACTION
> >> | RESTRICT}]
> >>
> >> Is there a default action for ON DELETE and ON UPDATE if no action
> >> is specified in the database definition?
> >
> >RESTRICT is, of course, the default 'action'. ON DELETE and ON UPDATE are
> >later additions.
>
> I see in the change notes that ON UPDATE was implemented in 4.0.8.
>
> But how can ON DELETE be a later addition than RESTRICT? I was under the
> impression that RESTRICT wasn't even implemented.
CREATE TABLE parent(id INT NOT NULL,
PRIMARY KEY (id)) TYPE=INNODB;
CREATE TABLE child(id INT, parent_id INT,
INDEX par_ind (parent_id),
FOREIGN KEY (parent_id) REFERENCES parent(id)
) TYPE=INNODB;
CREATE TABLE child(id INT, parent_id INT,
INDEX par_ind (parent_id),
FOREIGN KEY (parent_id) REFERENCES parent(id)
ON DELETE RESTRICT
ON UPDATE RESTRICT
) TYPE=INNODB;
the two definitions of 'child' above are equivalent. RESTRICT simply guards
the referential integrity constraint.
> Also, the manual lists SET DEFAULT as a reference option for the general
> CREATE TABLE syntax. Does that come into play for InnoDB at all?
ON ... SET DEFAULT is not implemented in InnoDB.
> >
> >...
> >
> >> Best regards,
> >> Tor Rune Skoglund
> >> [EMAIL PROTECTED]
> >
> >Heikki Tuuri
> >Innobase Oy
> >---
> >InnoDB - transactions, hot backup, and foreign key support for MySQL
> >See http://www.innodb.com, download MySQL-4.0 from http://www.mysql.com
>
>
> --
> Paul DuBois
> http://www.kitebird.com/
> sql, query
Best regards,
Heikki
Innobase Oy
http://www.innodb.com
InnoDB - transactions, foreign keys, and a hot backup tool for MySQL
sql query
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