Re: ADQL simplified

From: Wil O'Mullane <womullan-at-skysrv.pha.jhu.edu>
Date: Tue, 27 Jan 2004 19:19:09 -0500


> When you mention the query will " ... include a reference
> to the datacenter/registry entry it is expected to run on ",
> I'm assuming that since the ADQL will reference a particular
> table (VOResource) then its description should be same regardless
> at which data centre it as at (the same table might be
> replicated at various data centres).

To follow your SQL analogy you would assume that a table named X was the same in any SQL database.
This is probably not a particularly fair assumption.

ADQL allows for an alias representing the archive to appear in front of the table name.

There is noting in the ADQL spec as of now to force to destination of the query to be in the query. I do not think that is a necessary or good idea. It seems however some people feel ADQL will linger and they will be unable to know what it was meant to do and what the types of the columns were without know where it was intended to go to.
>
> So the column based type information need not be included
> in the ADQL itself, but it can be determined during query
> processing (ADQL->SQL).

Correct - each NODE publishes its type info and the assumption is the ADQL coming to it is in the correct types and UNITS!

But since SQL is as typeless as ADQL I fail to see what extra processing you have to do here. Received on 2004-01-28Z01:23:38