[ZODB-Dev] Proposal: cross database reference seat belt

[Jim Fulton]

On Apr 28, 2009, at 11:36 AM, Shane Hathaway wrote:

> Jim Fulton wrote:
>> Thanks for writing this up!
>> Do we really need per-object control?
>> It would be simpler to simply allow or disallow (new) cross-data   
>> references at the database level.
>> I think the most common use case for cross-database connection   
>> limitation is support for "mounts".  With mounts, there are a  
>> small  number of direct references between databases.  This could  
>> be  addressed by instantiating a database in a mode that allows  
>> cross- database references and using that instantiation to  
>> establish the  mounts. All other instantiations would disallow new  
>> cross-database  references.
>> Do you have a specific use case that requires _p_check_xref?
>
> No.  Good point.
>
> I am hoping that even after we configure the system to disallow new  
> cross-database references, we can still make other modifications to  
> the objects that contain cross-database references.

Right.

>  For example, if I have a site object containing a catalog in  
> another database, I should still be able to modify the title  
> attribute of the site, as long as I don't try to change the catalog.


Yup, although now that you mention it, I fear it will be hard to make  
this work. :) I need to think about it.

Jim

--
Jim Fulton
Zope Corporation