At Friday 20/1/2006 20:07, Jeff Gentry wrote:
As background, the primary class (A) maintains a handle to an instance of
another class (B) which handles interaction w/ a psycopg db
controller. Class A also will instantiate several instances of Class C
and as part of the construction will pass it the handle to class B. So in
summary, A has a B and has 1:n C's, and C has a reference to B. A & B
have physical representations in the ZMI, while instances of C are
'virtual'.
If you follow these rules you should be safe:
- Never store a reference to a persistent object inside another
persistent object; use its id or path to retrieve it when needed.
- Never store a reference to a persistent object inside a
non-persistent object.
- If a persistent object "owns" some other persistent objects, make
the first an ObjectManager.
- Let Zope manage transactions, and avoid bare try/excepts
Of course you can break the rules if you really really know what you
are doing but they are a good starting point. And reading about how
persistence works is a big help (it appears you've already read it, I think).
Gabriel Genellina
Softlab SRL
_______________________________________________
Zope maillist - [email protected]
http://mail.zope.org/mailman/listinfo/zope
** No cross posts or HTML encoding! **
(Related lists -
http://mail.zope.org/mailman/listinfo/zope-announce
http://mail.zope.org/mailman/listinfo/zope-dev )
