From: [email-masked] (N L Sarda)
Date: Wed, 5 May 93 18:40:46 IST

This  is  in  reply  to the message from  Rick.  His  message  is 
reproduced below :
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I think	that Nandlal's classification scheme has a lot going for it.
The user's point of view has the advantage that	certain	types of
queries	that are expected to be	more frequent than others can be
emphasized.

I had a	difficult time understanding the classification	scheme,	perhaps
in part	because	the explanation	was necessarily	short. There is	at
most a sentence	or two on each of the portions of the scheme.

It also	is apparent that this classification scheme, while related in
some ways to Christian's proposal, is also a quite different approach
to organize queries. So	my question is,	is the proposed	scheme (1) an
addition to, (2) a modification	of, or (3) a replacement for the
existing strawman proposal?

If (1) or (2), could Nandlal modify the	strawman proposal,
incorporating his recommended additions/modifications, and post	a new
proposed classification	scheme?	If (3),	could Nandlal write it up, to
the level of specificity and detail of the existing strawman taxonomy
proposal, so that the community	could decide between them? Finally, it
would be very helpful if Nandlal could provide an approximate time
frame for doing	so. Much work needs to be done on the step following
the taxonomy in	the next six weeks, and	we need	to move	beyond the
taxonomy very shortly. (Of course, after the workshop there will be
the opportunity	to start on the	second version of the benchmark,
addressing things like aggregates; at that time	we could also address
improvements to	the taxonomy.

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I will refer to the taxonomy proposed by Christian simply as  CSJ 
Proposal in the following. It has the following advantages :

-   it   satisfies  the  three  criteria  listed  by   CSJ.   The 
classification  is  comprehensive  (within the  confines  of  the 
decision to exclude 'group-by' and 'having' features of SQL).
- it leads to identification of orthogonal components (which  are 
derived from SQL features).
- It provides for suitable naming of classes and categories. User 
oriented class names can be introduced here.

In my proposal, I took a different approach. I apologize for  its 
poor  readability  and inadequate explanations. I gave  a  syntax 
"road map" for defining various classes. I tried to keep out  any 
SQL  bias from classification (which probably is not  essential). 
My proposal intends the following :

- define classes which are user oriented
-  identify  more  likely classes to check that  these  are  more 
easily expressible in TSQLs
-  make  classification  at higher level  by  employing  temporal 
algebra level operations (rather than using only the time  domain 
operations in select and where clauses of SQL).

Rick's observations are well-taken. In response to the questions 
posed by him, my answers are as follows :

-  It is difficult to add to or modify CSJ's proposal to  include 
my suggestions because the approaches are quite different.
-  I could attempt to add the suggested classes (in my  proposal) 
as certain classes/categories in CSJ proposal in Sec. 1.3, but  I 
have problem in making them orthogonal.

Hence, I propose to make an alternative classification scheme.  I 
will try to prepare a 'strawman proposal' for it. I will also re-
structure my proposal totally to improve its readability. I  will 
also barrow from CSJ's proposal wherever necessary and  possible. 
It will probably be more SQL-oriented than my earlier proposal.

Time  frame  : I may be able to complete the  preparation  of  my 
proposal  by May 15, 1993. This may probably be too late for  the 
workshop. In that case, we could comment on it in future.