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Morten Gulbrandsen wrote:
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
7.5.5.2 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 worked.
Yours Sincerely
Morten Gulbrandsen
"Rasmus Lerdorf" <rasmus@lerdorf.com> schrieb im Newsbeitrag Pine.LNX.4.44.0310281902580.4315-100000@thinkpad.lerdorf.com">news:Pine.LNX.4.44.0310281902580.4315-100000@thinkpad.lerdorf.com...
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
MySQL.
My question is: can PHP give MySQL the missing relational properties?
Is it possible to remedy the limitations of MySQL concerning FOREIGN KEYS? Actions, REFERENCES and triggers
through PHP?
ON DELETE SET DEFAULT For instance: I think could be solved through additional coding, But what about the other missing SQL statements?
REFERENCES ON DELETE CASCADE ON UPDATE CASCADE
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
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