Registry query language

[Clive Page]

On Tue, 23 Sep 2003, Elizabeth Auden wrote:

> > What form should the registry query language take?
> > 1. an xml form of SQL (as for ADQL in the SkyNode document)
> > 2. Xquery
>
> My choice would be XQuery - I think it has more recent W3C standards than
> any of the SQL implementations, and XQuery also has the benefit of
> internet support and documentations from many projects on the web, not
> just VOs.

I think that I would also go for XQuery, though that depends to some
extent on the structure of the Registry.  SQL is designed to search single
tables or groups of related tables which it can join on the fly.  XQuery
is designed to search a hierarchical collection of information expressed
in XML.  It looks to me as if opinion is tending towards having a Registry
with at least some modest hierarchical structure (and that's my own
inclination as well), in which case XQuery will be a better fit than SQL.


-- 
Clive Page
Dept of Physics & Astronomy,
University of Leicester,    Tel +44 116 252 3551
Leicester, LE1 7RH,  U.K.   Fax +44 116 252 3311