Hi
Basically I have followed the call all the way to the execution of the
cursor.execute() on line 343 in models.fields.related.
I have not actually delved into the transaction method. However in my
setup I am using the django admin, I have not set up any automatic
transaction handling and the save method does is not transaction
managed. Also I am running this on an existing object, and even if I
was not, the primary key would have been created since the save method
is called before I add new m2ms.
Calling the super(Chapter,self).save() AFTER adding new m2ms is not
needed, nor does it work.
I also checked to make sure that the
django.models.fields.related._remove_items() method is not called
after the _add_items() method, to restore some previous state.
My only conclusion is that somehow the transaction of the save()
cancels out the transaction of the _add_items() method...
Maybe it's the
save.alters_data = True
flag?
or something to do with the dispatcher? I have not yet gone that deep
into the source...
But I can assure you that I am using as basic a setup as possible.
It is simply django admin, MySQL with InnoDB and that very save method
that you see in my initial post.
So repeating this should not be a problem...
I'll try to delve deeper into the transaction side of things, but any
insight you can give me would be appreciated.
//Dmitri
On Nov 7, 2:25 am, Malcolm Tredinnick <[EMAIL PROTECTED]>
wrote:
> On Wed, 2007-11-07 at 00:50 +0000, Dmitri Fedortchenko wrote:
> > Example code:
>
> > def save(self):
> > regex = re.compile("\{\{([^\}]{2,60})\}\}")
> > words = regex.findall(self.body)
> > self.body = regex.sub("\\1",self.body)
> > super(Chapter,self).save()
> > for word in words:
> > if len(word.strip()) > 0:
> > try:
> > self.keywords.create(value=word.strip().title())
> > except Exception, e:
> > print e
> > print self.keywords.all() # This prints the correct keywords!
> > super(Chapter,self).save()
>
> > The outcome of this code is that new Keywords are created, but they
> > are not bound to this Chapter.
> > Simply calling chapter.keywords.create(value="Test") will indeed
> > create a new keyword with the value "Test" bound to the chapter. I am
> > running this from the django admin btw.
>
> Can you explain what is meant to be going on here?
>
> If you are trying to save m2m relations for an object that has not been
> saved yet, you're out of luck. We need to know the current object's pk
> value before it can be used in a m2m table and that isn't always
> available (with auto primary keys).
>
> Normally, if you want to adjust the m2m relations for a model, hooking
> into the post_save signal is the way to go.
>
>
>
> > The problem seems to be in the
> > django.db.models.fields.related._add_items method, somewhere around
> > line 340.
> > The fact is that the insertion query is executed, but for some reason
> > it is not committed, perhaps it is a transaction issue?
>
> Perhaps it is. Perhaps it isn't. How have you established the query was
> executed? What does the commit_unless_managed() call end up doing in
> your case? It might depend on your particular setup, too. Do some more
> debugging and see what shows up if you think there's a problem there.
> However, do keep in mind that it's generally impossible to do everything
> with m2m's inside a model's save method because of the chicken-and-egg
> problem with primary keys noted above.
>
> Regards,
> Malcolm
>
> --
> Tolkien is hobbit-forming.http://www.pointy-stick.com/blog/
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