[Zope-CMF] Add properties to already existing content types

[Dieter Maurer]

Rainer Thaden wrote at 2003-6-17 18:22 +0200:
 > Hi,
 > 
 > i had to add some properties to a file system based class which
 > already had some instances in the ZODB.
 > I did it like this:
 > I defined a function do_update in the class and called the method on
 > all instances.
 > Here's the code:
 > 
 >     def do_update(self):
 >         id = self.id
 > 
 >         container = self.aq_parent
 >         ob = self
 >         
 >         ob.__dict__ = self.__dict__
 >         ob.__dict__['property1']=''
 >         ob.__dict__['property2']=''
 >         
 >         container.manage_delObjects(ids=[id])
 >         container._setObject(id, ob)

This is really funny code:

  The following should be almost equivalent:

      def do_update(self):
        self.property1= ''
	self.property2= ''

"manage_delObjects" will call "manage_beforeDelete"
and "_setObject" "manage_afterAdd". If they do something
essential for you (e.g. indexing), call them explicitly.

 > The problem is that the new properties are tuples by default. When i
 > debug in the edit method of the class and assign
 > 
 > property1='bla'
 > 
 > then i get property1=('bla') at the first time.
 > When i assign it a second time i get the correct result.

There is probably a trailing "," somewhere.

The code you show above will not assign a tuple.


Dieter