[orm-devel] Question: setting an object's many2one attribute to a "None" value

[Michael Watkins]

Works as it should - thanks, I'll back out my own hack and use your
code.

PS, is there anything in CVS that ought to prevent a Postgres instance
of ORM from working? Just thought I'd ask before I start heading down
the path to understand what I saw last night on a (very) quick test of
CVS ORM. 

Mike

On Sun, 2003-08-31 at 11:25, Diedrich Vorberg wrote:
> Hi Mike,
> 
> >Simply setting
> >
> >	product_instance.type_id = None
> >
> >Will fail of couse, since the class expects a dbobj on the right hand
> >side, not None.
> 
> Actually this is not an "of course", it's a bug in ORM! The case of a
> many2one relationship being set to None (which should set the
> corresponding forign key column in your product table to NULL) is not
> handled by ORM!
> 
> Here's a new version of many2oneColumn's set() method. I didn't test
> this, sorry...
> 
> Diedrich
> 
> ----------------------------------------------------------------------
> 
> class many2oneColumn(_2oneColumn):
>     def set(self, data):
>         """
>         You can only assign objects to a many2one-managed attribute
>         which are of the right type and have already been inserted
>         into the database. 
>         """
>         if data is None:
>             self.ds().update(self._dbObj, self._columnName, "NULL")
>             if self._columnName != self._attributeName and \
>                                 self._dbObj.columns.has_key(self._columnName):
>                 self._dbObj.__setattr__(self._columnName, None)
>         else:
>             if not isinstance(data, self._childClass):
>                 raise ObjectMustBeInserted(
>                     "You can only assign objects of %s to this column" \
>                                                  % self._childClass.__name__)
>         
>             if not data.oid():
>                 raise ObjectMustBeInserted(
>                     "You must insert a dbobj before you assign it to a " + \
>                                                         "one2one relationship")
> 
>             if self._dbObj.oid():
>                 fmt = data.primaryKeyValue().format()
>                 self.ds().update(self._dbObj, self._columnName, fmt)
>                              
>             # if there is a column Object representing the foreign key column
>             # set it to the value of the newly asigned object
>             if self._columnName != self._attributeName and \
>                    self._dbObj.columns.has_key(self._columnName):
>                 self._dbObj.__setattr__(self._columnName,
>                                         data.primaryKeyValue().get())
>         self._retrieved = 1
>         self._data = data    
> 
>