Re: RM formalism supporting partial information
From: paul c <toledobythesea_at_ooyah.ac>
Date: Tue, 20 Nov 2007 03:29:02 GMT
Message-ID: <2ws0j.12941$cD.10056_at_pd7urf2no>
>> Marshall wrote:
>>
>> ...
>>
>>>> The important concepts are tuples, propositions, predicates etc.
>>> For myself, I have found less and less use for the concept
>>> of tuple over time. I try as much as possible to do everything
>>> with just relations. Relations as sets-of-propositions, relations
>>> as predicates, cardinality-1 relations instead of tuples, etc.
>>> In fact I am going so far as to attempt the idea of a theory with
>>> relations as the only primitive. (And possibly also including
>>> scalars.)
>>> Not 100% clear if the idea can be carried out all the way, but
>>> it's promising so far.
>> (Forgot to ask this before). I notice that D&D depend on tuples to
>> define their GROUP operator. Is there a way to define a Grouping or
>> group-by operator with tuples?
...
Date: Tue, 20 Nov 2007 03:29:02 GMT
Message-ID: <2ws0j.12941$cD.10056_at_pd7urf2no>
Marshall wrote:
> On Nov 19, 3:35 pm, paul c <toledobythe..._at_ooyah.ac> wrote:
>> Marshall wrote:
>>
>> ...
>>
>>>> The important concepts are tuples, propositions, predicates etc.
>>> For myself, I have found less and less use for the concept
>>> of tuple over time. I try as much as possible to do everything
>>> with just relations. Relations as sets-of-propositions, relations
>>> as predicates, cardinality-1 relations instead of tuples, etc.
>>> In fact I am going so far as to attempt the idea of a theory with
>>> relations as the only primitive. (And possibly also including
>>> scalars.)
>>> Not 100% clear if the idea can be carried out all the way, but
>>> it's promising so far.
>> (Forgot to ask this before). I notice that D&D depend on tuples to
>> define their GROUP operator. Is there a way to define a Grouping or
>> group-by operator with tuples?
> > Um, I forget: their GROUP is not the same thing as SQL group-by, > right?
...
The way I think about it is that their GROUP groups the attributes that aren't SQL's GROUP BY-ed columns, like yin and yang. Received on Tue Nov 20 2007 - 04:29:02 CET