Lorenzo Gil Sanchez wrote:
Hi,
I have a question about updating the objects in a ZODB. Suppose I
already have 100 objects of class A and then I modify class A adding a
new attribute. Then I craete a new object of the class A and now I
have two kind of instances of my class A, the old ones and the new one.
How do I update the old objects and add the new attribute to them? I
can provide a default value for this attribute if that helps.
You can just add the new variables as a class variable.
class SomeOldClass:
newVar = ''
....
Or you can make a mixin class for compatibility. This can make your code
a bit more readable.
class Compatibility:
# added in ver. 1.1
newVar = ''
class SomeOldClass(Compatibility):
...
Or you can use setter and getter methods.
class Compatibility:
def getNewVar():
return geatattr(self, newVar, '')
--
hilsen/regards Max M, Denmark
http://www.mxm.dk/
IT's Mad Science
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