Re: Comments against TMQL draft 2006-02-22

* Robert Barta
>
> TMQL does not use a 'default namespace', otherwise it would have said
> so, but it does not. The reason why
>
>    jack / name
>
> should work is that 'name' is a _valid_ item reference of a topic in
> every map(!) for the TMDM concept
>
>    http://psi.topicmaps.org/iso13250/glossary/topic-name

We haven't spelled that out anywhere, have we?

> I think you are right, but I cannot find a place where
>
>    http://psi.topicmaps.org/iso13250/model/
>
> is defined as namespace. Could be just me being tired.

This is for the TMDM -> TMRM mapping to do. But I had to put off  
writing that until after the Oslo meeting. :-(

> Definitely. In fact, I would love to see this whole axes business move
> into TMDM at some point. It has nothing to do with TMQL, not?

I'm surprised by this. Why isn't navigation along axes a QL thing?

(In any case, as you've noted, TMDM really is set in stone. We can't  
even fix the bugs.)

> So this means that 'class' should be replaced with 'type'. And
> superclass with supertype...

?

> In almost all languages there is a huge difference between & and &&
> and | and ||. So also in TMQL:
>
>   & symmetric, non-short circuit AND
>   && does not exist in TMQL
>   | symmetric, non-short circuit OR
>   || asymetric, short-circuit OR (can be defined via if-then-else)
>
> This is the same in Java, which got it from C++ which got it from  
> C.....
>
> I would not advise to switch & to short-circuit because this can
> dramatically undermine automatic optimization.

I really don't know what "short-circuit" means in a query language.  
It would be helpful if you explained how you interpret this.

--Lars M.