-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 03/10/2013 04:19 PM, Joshua Immanuel wrote:
My application is based on Grok. Whenver, I change a method-name or add a method to a Model, Grok fails to load the previous version from the ZODB. I resorted to writing simple generations (zope.generations) to update the stored model objects.
For 'method name' changes, this basically means: 1. create new object 2. copy every single attribute of old-object to the new-object 3. delete old-object 4. save new-object
How does everyone else do this? Or is there a way to make grok/zope/zodb not persist the method-names and signatures in a content component (grok Model)?
Method names are not stored in the ZODB at all: only the instance attributes are stored. What you report doesn't correspond with how ZODB is designed, nor with how Zope has been using it forever. For instance, I can create a class inside a module:, derived from Persistent: # foo.py, v1 from persistent import Persistent class Foo(Persistent): def __init__(self, bar, baz): self.bar = bar self.baz = baz and make instances of it, adding them to another persistent object: from ZODB.DB import DB from ZODB.FileStorage import FileStorage db = DB(FileStorage('/tmp/data.fs')) conn = db.open() root = db.root() from foo import Foo root.foo = Foo('bar 1', 0) import transaction transation.commit() and then later modify 'foo.py', adding methods to the Foo class # foo.py, v2 from persistent import Persistent class Foo(Persistent) def __init__(self, bar, baz): self.bar = bar self.baz = baz def spam(self): return self.bar * self.baz and still load the previously created object from the database:: from ZDOB.DB import DB from ZODB.FileStorage import FileStorage db = DB(FileStorage('/tmp/data.fs')) conn = db.open() root = db.root() from foo import Foo assert isinstance(root.foo, Foo) print root.foo.spam() If that isn't working for your models, you must be doing something very weird. Possible issues: - - Do your model classes derive from Persistent? - - Do they have attributes with multable values (e.g., native Python dict or list)? If so, does your code mutate those values without telling the containing object it has changed? - - Are you remembering to commit the transaction? Tres. - -- =================================================================== Tres Seaver +1 540-429-0999 tseaver@palladion.com Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlE9UFkACgkQ+gerLs4ltQ6euQCeORe7UvO3a4VK8oAP+pvd7Rce lL8An1TxxJcb48YjFa9Ih67U7N1Y57cl =2eUa -----END PGP SIGNATURE-----