[Twisted-Python] Re: assignKeyAttr in row object

[Tsai Li Ming]

Tsai Li Ming wrote:
> Dave Peticolas wrote:
> 
>> On Tue, 2004-10-05 at 05:15, Tsai Li Ming wrote:
>>
>>> Dear all,
>>>
>>> What is the assignKeyAttr method used for in a row object? Is it 
>>> similar to a primary key that can be used to identity the instance?
>>
>>
>>
>> Yes, assignKeyAttr is used to change the primary key of a row object.
>>
>> dave
> 
> 
> Hi Dave,
> 
> Is it necessary to use assignKeyAttr? From the source code, it doesn't 
> seem to do anything special, except to change the primary key(s)?
> 
> def assignKeyAttr(self, attrName, value):
>         """Assign to a key attribute.
> 
>         This cannot be done through normal means to protect changing
>         keys of db objects.
>         """
>         found = 0
>         for keyColumn, type in self.rowKeyColumns:
>             if keyColumn == attrName:
>                 found = 1
>         if not found:
>             raise DBError("%s is not a key columns." % attrName)
>         self.__dict__[attrName] = value
> 
> Alternatively, I could set the primary key manually.
> newRoom = RoomRow()
> newRoom.roomID = get_unique _id()
> #newRoom.assignKeyAttr("roomID", get_unique _id())
> reflector.insertRow(newRoom).addCallback(onInsert)
> 
> Liming

My mistake. Twisted has the __setattr__ defined so that key values must 
be changed via assignKeyAttr.

Liming