On Fri, 30 Jan 2004, Noel Winstanley wrote:
> I tried and I failed.
>
> I can;t get any joy with the latest version of ADQL.
> I'm really beginning to wonder whether ADQL is the most suitable query
> language for astrogrid datacenters. What are its benefits?
I agree with your comments, Noel, and I've been asking for some time why we need ADQL. The only answer I was able to get was that it made the checking of the query simpler and improves security. I am not convinced that we need to be all that fussy in checing syntax: if the user generates the query from our menu-style registry-driven portal then it will be hard to make a syntax mistake; power users who generate their own SQL by typing it into a text box will find out soon enough if they make a mistake: any DBMS parses the query and returns an error message instantly. The experience of JHU with their skyserver was given at the last ADASS meeting by Wil O'Mullane: indeed he made a mistake in his live demo and got a message back, allowing him to correct it. This isn't a perfectly user-friendly system, but it seems adequate to me. As far as security goes, a simple solution initially is to restrict the first keyword of any query to be SELECT, and in particular prevent non-authenticated users from issuing DROP or DELETE statements. Later, maybe, we can allow things like CREATE TABLE, INSERT, UPDATE, and so on. That shouldn't be all that hard even without ADQL.
-- Clive Page Dept of Physics & Astronomy, University of Leicester, Tel +44 116 252 3551 Leicester, LE1 7RH, U.K. Fax +44 116 252 3311Received on 2004-01-31Z17:45:02