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

[Diedrich Vorberg]

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    



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           _..._                            Diedrich Vorberg
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