[Zope] Creating properties in python products

[Dieter Maurer]

Georges Baladi writes:
 > I have developed some custom products in python and this products has =
their own=20
 > properties. Later I need to creat new basic properties. The objects wi=
th only=20
 > the initial basic properties acquire the new properties but objects th=
a has=20
 > other properties (created in the management interface) don=B4t. And be=
cause in=20
 > this objects the other properties has the same name that the new basic=
=20
 > properties ever if I delete the other properties I can=B4t create (in =
the=20
 > management interface) an propertie with the same name tha the properti=
e defined=20
 > in the python product (but no propertie with this name are show in the=
=20
 > management interface). I am using Zope 2.3.3.
This is as one would expect...

  The class contains a "_properties" describing the default
  properties. This is a tuple.

  When an instance changes its properties, modification
  are done on a local copy (and, of course, not in the
  class's "_properties"). From then on, the linkage
  between class properties and instance properties is
  broken - as you described.

You can use "PropertySheets" instead of "_properties".
They are (a bit) more versatile but you may still
experience surprises....


Dieter