[Zope] Re: Pluggable brains sample using Script (Python) (J Cameron Cooper)

[J Cameron Cooper]

>
>
>BTW, I noticed that once you get an instance of the object, you *can* read
>the attributes (which of course correspond to the columns from the SQL
>query), but it doesn't let me change the values unless I create "wrapper
>methods" inside the class.
>
>Is that a Zope security thing, bug, unimplemented feature... do you know?
>  
>
I guess I can't really say, in that I don't have time to take a look at 
the source right now. If you would like my guess (which may very well 
not be worth the paper which it is not written on), I think this is 
probably intentional. Why?

1) it probably had to be expressly prohibited
2) allowing change to PBs would imply (to some, at least) a change in 
the source data, which doesn't happen.

Unlike some of the newer parts of JDBC, changing the results of an SQL 
query in Pluggable Brain space does not have any effect on the actual 
stored data. If it did, it would be a nice little feature, but otherwise 
it would be an annoyance and (possibly) inconsistent. Depending on your 
mental model of how this sort of mapping works. So I imagine that 
locking it down was the most reasonable behaviour. (There are other 
areas in Zope, I believe, where this happens.)

If you like, you can think about it as an unimplemented feature that has 
been safeguarded, although I doubt this was ever the original intent.

Someone with reasonable SQL knowledge and a good bit of expertise into 
Zope/Python introspection might be able to make this real without too 
much work (or maybe not.) But don't hold your breath.

          --jcc