[Zope-dev] ZPatterns: persistant objects hold DataSkin-Items -> KeyError: _v_dm_

[Ulrich Eck]

hi out there,

i use zpatterns/specialists for a Network-Documentation Tool.

I'm writing a Product which controls the relations between specialists
and manages multible actions (edit/new/delete) for ZPatterns DataSkinObjects
(DSO).

I have a Product-Instance of ZTWM (ZTransactionWorkflowManager) in my
application root which is a Folder by itself and holds as folder-objects its
'Transactions' (in this case a Transaction starts at the first edit-action
and lasts
til the last submit of a form with valid entries - e.g finish transaction.)

It behaves like a Wizard (PTK) with next/back/cancel/finish buttons and
reads
out the DataSkinPropertysheet for creating the edit/new forms on the fly.

One can also define relations between the specialists an they are used to
edit
Foreign Keys.

small painting here:

\application-root
--\<Person>    (specialist for persons)
--\<Komponent> (specialist for komponents)
--\<ZTWM>    (my TransactionWorkflowMangager - Folder)
---- \<1>    (first transaction -Folder)
-------\<1> (first transaction object - Folder)
--------| ds_object (attribute which references the DSO)
--------| more info on the current Transaction object
-------\<2> (second Transaction object)
--------| ds_object (attribute which references the DSO)
--------| more info on the current Transaction object
----\<2> (second Transaction)
...

so far about how it should work  ..

For each TransactionObject (TO) I save the Object I retrieved with
"specialist.getItem(id) == DataSkinObject(DSO)"
as attribute "ds_object" to the TransactionObject.

After I restarted Zope and want to replay/finish a transaction,

i get an KeyError, Value _v_dm_

the prefix _v_ stands for not pickeable (afaik)
dm for datamanager ?!?

ok .. i put a TO in the Transaction, get the actual DSO,
call the transactionmanagers editor function and a form with correct values
is displayed,
 i can  edit this form and call the DSO manage_changeProperties method from
the
transactionmanager.

when i don't finish a transaction and restart zope i still have my
transactions with proper
values saved in my TransactionManager - except the property "ds_object" wich
was assigned
to the DSO at TO-creation

when i try to set/get an attribute i get the KeyError of  "_v_dm " ...

I can deal arround that if i reget the DSO from the specialist in every
function which deals with DSO's.

is there a better way to

a) tell my TransactionManager that my attribute "ds_object" is not pickeable
(e.g. call it  _v_ds_object)
 and how to know if zope is restarted ?!?!?
or
b) store this object persistantly in my TO without showing it in the
folder-structure but behave like a DSO
 set/get attributes through Skinscripts

hope that i described clearly enough where my problem is ...

thanks for your reply

Ulrich Eck
net-labs