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Re: OODB query interface



[please don't write HTML mail to the list. Thanks.]

On Mon, 07 Aug 2000, Ola Berg wrote:
> >%_  >It should be dynamic and ad hoc while delivering responses from the query in both the OOdbms  >basic data along with procedures used to manipulate the data for its proper use (methods). 
> 
>   I agree in most parts, but I am not sure if the natural language approach is the right thing. Object-dot-notation is both precise, OO-friendly, and not too difficult to understand for a non-programmer. 
> 
>   For the most part, the database systems will be queried by programmers. If non-programmers queries them, they demand graphical user interfaces (which wasn't common when SQL was invented) anyway. 
> 
>   >While these function might reside and operate on top of an API. The API should be viewed as the >backbone for the feature listed above.
> 

>   Therefore, I suggest that the prime query language is the language of the
> API in an object oriented fashion, and that different graphical and natural
> language interfaces are implemented on top of that.

I perfectly agree here.

To be real object oriented the query interface has to provide a language
dependent API. This has to implement the query model (which we will have to
specify) into the underlying programming language. Front ends for that API may
be developed on top of that.

> 
>   But let's skip the skin and dive into the gore: what types of operation does it need to support?
> 
>   I have come up with three kinds, two of which operates on sets (or bags) of objects, and one that operates on objects:
> 
>   1) Normal set algebra on objects (joins etc)
> 
>   2) Filtering, that is selecting subsets of objects that meet certain criteria (like WHERE clauses)

Exactly. We need a way to define sets (subsets) of objects (filtering) and set
algebra functions to be used with these sets.

>   3) Following references.
Why? Can you explain more?


Falko
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______________________________________________________________________
Falko Braeutigam                              mailto:falko@smb-tec.com
SMB GmbH                                        http://www.smb-tec.com