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RE: OOQuery Language



I'm starting a crude implementation of OQL queries for ozone. I'm using it 
at the beginning of an XML based report generation engine. The query defines 
the data content of a report and subsequent XML/XSL/XSLFO documents define 
the structure and display format of the output. This enables me to define a 
report through a series of XML/XSL/XSLFO documents without writing any code 
and then publish the report as XML, PDF or on screen as well as printing it 
out.

I've chosen OQL since it is reasonably well-known and well-defined, it is 
much simpler to fit to an OODBMS than SQL, and it has grammers available.

Although I think the query-kernal is ultimately the way to go, my need to 
get a product out the door and my limited programming skills preclude me 
from taking on the implementation of a general solution such as that.

My crude implementation will focus on the subset of OQL I need and be 
oriented to the specific structure of our application. For example our query 
results will be hierarchical composites rather than simple sets or bags.

Still this work may be useful to others as an example and a basis for their 
solutions and a more comprehensive one and I'd be glad to pass the work 
along as an example rather than a tool or framework.

Although I can understand the desire for a more OO query, my brief survey of 
the genesis of OQL and other attempts at OO query languages convinced me the 
definition of a robust new OO query language is not a trivial task. Although 
S.O.D.A. and other alternatives may look interesting, AFAIK they don't have 
a complete, rigorous definition to base an implementation upon. This is why 
I chose not to participate in  the earlier request related to implementing 
S.O.D.A. OQL may not be elegant, truly OO, or computationally complete but 
it's servicable.

don

>
>On Thu, 14 Sep 2000, Knapp, Robert \(CAP, CMC\) wrote:
> > >%_Falko,
> > 	From what I'm reading here (and I really just skimmed it)
> > it sounds like you object (and your reasons are sound) to
> > having OOQL built into Ozone.
>Do you mean ODMG OQL? I assume yes.
>
> > How about building an OOQL to Ozone bridge, that would do all of the
> > by hand work?
> >
> > Here's my example.  I'm working on a Laboratory Information Management
> > System, one of the basic requirements for most labs is a SQL-like 
>language
> > so that they can print reports and such.
>I understand this requirement. What about a XML interface for reports and 
>such?
>
> > If someone were to build a bridge(separate from ozone) that accepted
> > queries and spit back collections, would that be an acceptable solution? 
>To
> > both you and the people in need of ooql?
>In general, even OQL is "acceptable" for me. I just said that am not going 
>to
>work on OQL support for ozone now or later.
>
> >
> > I've been following this list for a while, and it looks like
> > Ozone suits 75%+ of our needs(which to date seems to
> > be more than anyone else!),
>:)
>
> > so I'd like to try and figure
> > out some way to make everyone happy here.
>Thank you, Rob. These are very good points.
>
>Conclusion:
>- descriptive query lang(s) is(are) needed
>
>- an independent query-kernel seems a good way to implement the pure query
>functionality
>
>- different fron-ends can use this kernel to provide the different APIs 
>(OQL,
>SODA, 'XQL')
>
>
>Falko
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