[Zope] InvalidObjectReference strikes

[Jurgen Defurne]

On Sat, Aug 21, 2004 at 09:23:57AM +0200, Chris Withers wrote:
> Jurgen Defurne wrote:
> >Error Type: InvalidObjectReference
> >Error Value: Attempt to store an object from a foreign database connection
> >error.
> 
> You're attempting to storea persistent object in a session this is
> "bad" (tm).
> 
> >Does anyone have a clue how I can copy the contents of the query result 
> >into a
> >Python array or dictionary in Zope ?
> 
> Show us the code of what you're trying to do and maybe we can sugges an 
> alternative...

I don't think that that is necessary anymore. Your comment about the
persistent object finally makes everything clear what I have been reading in
the Zope documentation, but nowhere in the documentation is it explicitly
stated that the result of a query is a persistent object.

Also, the comments in the Zope book about "Mounted Transient Object
Container Caveats" are not really clear and they certainly give no clue on
what to do.

However, because of your question about the code, I started thinking 'what is
my real objective here ?'. 

My objective is to create a batch query thing, so that I can browse forward
and backward through a query. I have generic procedures for initialising the
browsing, going forward and going backward. These take a dictionary of fields
and a ZSQL method. 

The error I made in my code was that a) I do need what I call a 'browse'
object, which keeps the reference to the ZSQL method, the number of lines to
query and the offset, and this object should (and can) be kept in a session,
but b) I do not need to have the result of the query in session storage. This
is clearly a mistake.

So the lesson is, do not use the session storage for just passing a result!

It is much better to declare a global variable myself into which I should pass
intermediate values and query results between methods.

Thanks for clearing things up and making me think.


Regards,

Jurgen


> 
> Chris
> 
> -- Simplistix - Content Management, Zope & Python Consulting -
> http://www.simplistix.co.uk