VOQL sessions in Beijing and DAL-VOQL joint sessions

Alex Szalay szalay at jhu.edu
Fri May 4 13:38:18 PDT 2007


on ORACLE -- indeed not strictly verbatim compliant, but 
by and large has the same functionality. The above links
show the translation


-----Original Message-----
From: owner-voql-teg at eso.org [mailto:owner-voql-teg at eso.org] On Behalf Of
Doug Tody
Sent: Friday, May 04, 2007 1:52 PM
To: Francois Ochsenbein
Cc: voql-teg at ivoa.net
Subject: Re: VOQL sessions in Beijing and DAL-VOQL joint sessions

On Fri, 4 May 2007, Francois Ochsenbein wrote:

> I could try to talk about the metadata requirements -- but the 
> information_schema being something existing almost only in SQL server, 
> I don't feel it would be wise to insist on this solution.
> Cheers, francois

Probably the implementation of information_schema is pretty mixed, although
I got the impression that MySQL and PostgreSQL have a pretty good
implementation as well, and possibly DB2 and INFORMIX (but not Oracle
evidently).  And of course SQL Server.

I suggest we consider the issue of an information_schema like approach, and
the issue of whether to use the information_schema specification directly,
as two separate issues.  The key question is what metadata is required to
compose non-trivial queries, as opposed to discovery/planning via the
registry, where only very limited information is required, and whether these
are the same or distinct.  I just would hate to see TAP crippled by an
approach which can't easily grow to support more sophisticated applications,
and efficient execution of complex queries against large tables.

 	- Doug

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