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Hi,
Le vendredi 4 février 2011,
Michael Seifert michael.seif...@gmx.net a écrit :
==
Hello everyone,
I recently started a Zope3 project, but I am stuck at the very
beginning. Although I have some experience with Zope2, the more
flexible approach to developing web applications was giving me a
really hard start. Let me point out my situation:
I created a container hierarchy which is stored in ZODB. Say I have a
set of object types A, B, C, D, whose relationships look like the
following (edges represent containment, i.e. A contains B,... where B
and D are in subcontainers of A):
A
/ \
B D
|
C
C has an attribute referencing an object of type D. As this attribute
is mandatory on creation, I created a vocabulary, which ascends the
hierarchy from the current context until it reaches A and returns all
objects of type D.
Now the part that doesn't work:
While ascending from C to B and from B to A works fine, descending
from A to D returns a security proxied object and since these objects
cannot be pickled, I cannot store it's reference in the attribute of
C.
1. Is this the way it's meant to be done? :) What is your opinion of
storing B and D objects in subcontainers of A?
That shouldn't be a problem, it's not different when you use a basic
folder-like container which, internally, stores sub-objects in an
internal b-tree container ; the only difference here is that you own
two internal containment attributes.
2. Are there any means to turn the vocabulary into trusted code, so it
will not be encapsulated in a proxy (without deactivating the security
proxy)?
Perhaps can you use the removeSecurityProxy function ?
3. How do you reference objects like you do with foreign keys in
relational databases? I want to do this to prevent objects from being
saved multiple times.
If the targetted object is persistent (and so a subclass of
Persistent class), it should be stored only once in the database
(just try to alter properties of an object and check if the other one
is also modified or not to check !)
Another way I commonly use to store references is to store only an
IIntIds utility reference, which is an integer ; the benefit of this
is that this value can easilly be indexed.
Regards,
Thierry
- --
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Office National des Forêts - Département Informatique
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Tél. : 01 40 19 59 64
Fax. : 01 40 19 58 85
Mél. : thierry.flo...@onf.fr
Web. : http://www.onf.fr
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