On 15/02/2007, at 10:48 PM, Juergen Saar wrote:
> For solving such kind of problem,
> we created views in the database.
Thanks for this note. In our case we want to avoid that mainly
because we want to maintain compatibility with different databases
I'd rather do this in Cayenne. Now I understand we can create an
SQLTemplate and work with raw data rows, but that comes with a few
inconveniences.
Today I stumbled on 'derived dbentities'. I could find nothing in the
documentation about them and not a lot in Javadocs. My questions
about them are:
* are they a fully support Cayenne feature which is sticking around
in the long term?
* what does ".. mean in the spec column and what else can I put
there? Can I put "COUNT(SELECT some other table)" there?
* if I add extra fields to the derived entity are they then simply
ignored for the purpose of committing data back to the database?
* can I now point my objEntity to this derived dbEntity instead of
the original 'real' dbEntity? Will everything continue to work as
before except I get to use a couple of new virtual fields? If that is
the case, why do we even need derived dbEntities and why can't we
just add additional virtual fields to the 'real' dbEntity?
Sorry for lots of questions, but I'd like to understand these thing
better since they look like they might be really useful.
Ari Maniatis
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