Chris Raber wrote:
>
> Eric writes:
>
> > I'm a bit surprised that Chris from GemStone didn't mention
> > queries over EJB objects; maybe in our various prototyping
> > and development efforts we have not as yet reached the
> > stage where such proven access paradigms are needed?
> >
> Could you elaborate please?
I don't have a specific context.
But, I think one of the important mechanisms for accessing an
information source (here one powered by an EJB server) is a
query language (preferably with some object capability).
However, I don't see query language in the client access
portions of the scenarios I'm reading on this list.
So, I understand that my EJBs can query the OODB store, but
how, in general, should my clients query my EJBs?
Even asking this question might presume that I have fine-grained
EJBs, or that I have a very large system.
> My thoughts on queries in general are:
>
> - Depending on complexity, you might be well served by
> direct SQL from session beans and batch returning of result
> sets (the WL folks are promoters of this), OR
>
> - If the "query" involves complex rules (object domain behavior)
> you'll be traversing a graph (which could be an object graph
> or finder's on entity beans...).
>
> Either way, care must be taken not to return huge results sets
> directly clients. And better to return a list of strings to display
> with keys back to the objects they are from, than to return
> remote entities from which text is then gotten to populate GUI
> widgets, one entity at a time.
Agreed.
Especially nice if the same basic approach can support both
LAN-connected clients (reasonable bandwidth and high availability)
and potentially disconnected clients.
Perhaps the same corpus of EBs can be queried by different varieties
of SBs.
> Curser behavior is usually need to scale, and this belongs in the
> coarse grained interface of a session bean.
>
> If you post some specific context we can drill down.
>
> Regards,
>
> -Chris.
>
> ----------------------------------------------------------------------
> Chris Raber, Systems Engineer, GemStone Systems Inc.
> 100 West Big Beaver, Suite 200, Troy, MI 48084
> phone: (248)-680-6691, fax: (248)-680-6689,
> email: [EMAIL PROTECTED]
> web: http://www.gemstone.com/
> ----------------------------------------------------------------------
--
Eric Hughes The MITRE Corporation [EMAIL PROTECTED] 781-271-7486
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