Hmpf:
I've just discovered that the framework also raises some of the
exceptions that I'd like to get rid of:
-> Look into backends/rdbms_common.py:
   This raises KeyError for several conditions:
   - trying to set reserved properties like creation or id
   - trying to change a retired item
   ...
   Or ValueError:
   - Trying to set a value that already exists
   ...
   Or IndexError for some consistency-checks with Link properties

I'm not sure if digging into this is really worth the effort.
On the other hand these are database consistency checks that should get
to the user (I've verified that for example trying to change a retired
item *does* hit the user, it would probably be better to check for this
in the html framework and not offer an editable field in that case :-)

But I'd really like to reserve the generic errors to python programming
errors that raise a traceback. And raise some "DatabaseConsistencyError"
or similar in case on of the other conditions fails.

Thoughts?
Ralf
-- 
Dr. Ralf Schlatterbeck                  Tel:   +43/2243/26465-16
Open Source Consulting                  www:   www.runtux.com
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