Dear Mr Lerdorf,

ON DELETE SET DEFAULT is not implemented,

According to my database textbook,

The propagate (CASCADE) option for the referentiel triggered action should
be specified on the foreign key in the relation corresponding to the
multivalued attribute for both on update and on delete.

According to Heikki Tuuri :

I think triggers should come in MySQL-5.1 or 6.0. I am not sure when I
willwrite support for ON DELETE SET DEFAULT. User demand for it has not
beenthat big.

According to Mysql reference manual FOREIGN KEY Constraints

A deviation from SQL standards: if in the parent table there are several
rows which have the same referenced key value, then InnoDB acts in foreign
key checks like the other parent rows with the same key value would not
exist. For example, if you have defined a RESTRICT type constraint, and
there is a child row with several parent rows, InnoDB does not allow the
deletion of any of those parent rows.

A deviation from SQL standards: if ON UPDATE CASCADE or ON UPDATE SET NULL
recurses to update the SAME TABLE it has already updated during the cascade,
it acts like RESTRICT. This is to prevent infinite loops resulting from
cascaded updates. A self-referential ON DELETE SET NULL, on the other hand,
works starting from 4.0.13. A self-referential ON DELETE CASCADE has always

Yours Sincerely

Morten Gulbrandsen

"Rasmus Lerdorf" <[EMAIL PROTECTED]> schrieb im Newsbeitrag
> Your question makes very little sense to me.  PHP is not a database
> obviously.  Also, MySQL has foreign keys and triggers and it can do
> cascading actions.  So I don't understand what you are talking about.
> -Rasmus
> On Tue, 28 Oct 2003, Morten Gulbrandsen wrote:
> > MySQL as database for PHP,
> >
> > Hello Programmers,
> >
> > MySQL is performing very fast and runs rock stable under high load,
> > But it is not ANSI SQL compatible.
> >
> > I have an interesting thread about this issue under
> > Newsgroups: comp.databases.theory
> >
> > Subject: Re: Is mySQL a RDBMS?
> > This also contains SQL code incompatible to the present version of
> >
> > My question is: can PHP give MySQL the missing relational properties?
> >
> > Is it possible to remedy the limitations of MySQL concerning
> > Actions,
> > and triggers
> >
> > through PHP?
> >
> > For instance: I think could be solved through additional coding,
> > But what about the other missing SQL statements?
> >
> >
> >
> > I feel the basic database functionality has to be
> > Implemented without PHP, PHP is an interface between the relational
> > database,
> > the web server and the browser and is
> > Not suited to code beyond the limitations of any relational database.
> >
> > Is this correct ?
> >
> > In other words,
> > has anyone succeeded in implementing an SQL RDBMS solely in PHP ?
> >
> >
> > Yours Sincerely
> >
> > Morten Gulbrandsen
> >
> >

PHP Database Mailing List (
To unsubscribe, visit:

Reply via email to