Re: TMQL: Direct (super|sub)types?

Lars,

On 3/2/2011 5:01 PM, Lars Heuer wrote:
<snip>
>> I think the TMQL standard is the right place to establish a clear
>> terminology for this distinction since everybody tackles this issue
>> a little bit different. Some call it "direct" or "deep" or whatever.
> Okay, personally, I'd start with a minimal/pure model/syntax for TMQL
> and enhance it later. If there is enough demand to introduce new axes,
> it's possible to introduce them later.
>
> I don't deny that you've found use cases, but I wonder if it belongs
> to TMQL. And if we don't introduce it yet, the user can still solve
> the problem by using associations. If we don't introduce the axes
> we'll loose nothing. The queries would be slightly longer, though.
>
> I'd think it easier to add something if we encounter a demand than to
> remove something. So, I'd opt for minimalism/purity.
>

I am not entirely sure I agree with LMG that we have several axes that 
are not distinguished by syntax, mostly because I think of 
supertype/subtype as one axis, and the current discussion being how far 
by default, "down" the axis a request for sub-types "goes."

To avoid my earlier typos, ;-),

class -> subClass1 -> subClass2

The question being does a request for subclasses of class return 
subClass1 (the "direct" case) or does it include subClass2 (the 
"indirect" case).

Since LMG mentioned that it was found useful to have a special construct 
for the "direct" case, my suggestion was that we make that the default 
and yet at the same time provide an operator for the second case.

I don't agree that Heuer has the minimal case because if we default to 
the "indirect" case, then implementors or perhaps query writers, are 
going to have to create filters on their own to achieve the "direct" case.

That is we will be creating a situation where non-standard solutions are 
necessary.

My suggestion is we not let that particular genie out of the bottle, at 
least not for this operator and take that as a pattern for others as well.

Bouncing into a conference call but will be back online in a bit.

Hope everyone is having a great day!

Patrick


-- 

Patrick Durusau
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