[ZDP] BackTalk to Document Zope Developer's Guide (2.4 edition)/ZODB Persistent Components

webmaster@zope.org webmaster@zope.org
Sat, 16 Nov 2002 03:55:46 -0500


A comment to the paragraph below was recently added via http://www.zope.org/Documentation/Books/ZDG/current/Persistence.stx#2-58

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    To resolve a conflict, a class should define an
    '_p_resolveConflict' method. This method takes three arguments.

       'oldState' -- The state of the object that the changes made by
       the current transaction were based on. The method is permitted
       to modify this value.

       'savedState' -- The state of the object that is currently
       stored in the database. This state was written after 'oldState'
       and reflects changes made by a transaction that committed
       before the current transaction. The method is permitted to
       modify this value.

       'newState' -- The state after changes made by the current
       transaction.  The method is *not* permitted to modify this
       value. This method should compute a new state by merging
       changes reflected in 'savedState' and 'newState', relative to
       'oldState'.

      % Anonymous User - Nov. 16, 2002 3:55 am:
       Does it return anything useful - I'm assuming it does (the new state, perhaps) as newstate (below) is
       described as not valid for changing. But what's the actuality?