Re: on primary keys (moved from Maypole list)

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On Wed, 2 Feb 2005, Perrin Harkins wrote:

> On Wed, 2005-02-02 at 12:03 -0500, Dana Hudes wrote:
> > integrity. The MySQL crowd of course say "you don't", "the database 
> > doesn't care" and "deal with it in your application".
> > Those of us using real RDBMS , where the R stands for Relational , like 
> > PostgreSQL , Oracle , Sybase etc. , do care about referential integrity.
> > So we want our library to care too :-)
> 
> This is FUD.  MySQL has supported referential integrity for years.

Oh ? Are you sure ? I'm going by the book on MySQL I've got  here.
_MySQL_ by Paul Dubois. It says that the SQL for foreign keys is parsed
but ignored. Now this particular book is copyright 2000 by New Riders.
Perhaps it is out of date as you say.
On p174, it says regarding FK:
	The reasons MySQL doesn't support them are due primarily to
	certain negative effects of foreign keys on database performance
	different than you will find in some other database literature,
	where you often find them described in terms such as "essential".
	The MySQL developers don't subscribe to that view.

That last line is pretty damning. 
Elsewhere it talks about supporting the SQL to make porting easier so that 
you don't have to rewrite your code. It just ignores your constraints.
All of them, not just FK.