Re: [SQLObject] SQLObject 0.6 (and 0.5.3)

[Ian B. <ia...@co...>]

Marcin Wojdyr wrote:
> On Wed, 22 Sep 2004, Ian Bicking wrote:
>>For a more complete list, please see the news: 
>>http://sqlobject.org/docs/News.html
> 
> 
> And there: 
> """
> Col constructors now support cascade: [...]  The constraints 
> are only implemented in the DBMS, not in SQLObject (i.e., they will not 
> work in databases like MySQL and SQLite)."
> """
> 
> I mentioned in 
> http://sourceforge.net/mailarchive/message.php?msg_id=9497517
> that it works in MySQL. SQLObjects throws an SQLObjectIntegrityError
> when I try to delete constrained row. Is this an experimental feature?
> Should I expect that it will be removed in future?

It is a bit experimental.  It was added by Sidnei de Silva, and I 
haven't fully thought about what it implies.

My goal is to change columns so that they receive event notification, 
e.g., an onDelete method is called.  Well, joins as well, since in this 
case the MultipleJoin would be doing the cascade.  Which is kind of the 
opposite of cascade, which is defined on the ForeignKey.  Hm... I'm 
still thinking it through.  So... I guess we actually need events across 
SQLObject instances; in this case, the class with the ForeignKey wants 
to get events from the class it's joined to, or more specifically a 
specific instance is interested in the events of some other instance. 
But lazily, since we obviously don't want to bring in the joined class 
just to register the event, because then fetching one object could pull 
in a huge set of objects.

Well, it's there.  I think the interface that's in SQLObject will 
probably stay, but the semantics will change some.

-- 
Ian Bicking  /  ia...@co...  /  http://blog.ianbicking.org