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
This is one of the many cases where I'm not sure I know enough to make an intelligent choice. I can understand how to write SQL (or some XML-parsed version of it) to do the kinds of queries that I might want for a registry, but I don't have the sense of what these might look like in XQquery. Here are a couple of example queries in pseudo-SQL. Could someone suggest what they might look like in Xquery?
Tom
In these pseudo-SQL I'm assuming there is a single 'registry' table that includes both DataCollection entries and service entries and that the linking fields discussed in the telecon today between data collections and services exists (and is saved as a concatentation of the collection id strings)
A very simplified version of what the DIS service does..
select service_name, short_name, curator, instrument from registry where
type='Catalog' and service_type='Cone'
A query for services that can access any existing database of X-ray information where the collection has resolution > 1' and the service has an SIA interface
select services.service_name from registry services, registry collections
where collection.spectral_regime = 'X-ray' and
collection.spatial_resolution < 1/60. and
collection.service_type = 'DataCollection' and
registry.linked_resources like '% '+databases.id+' %'
registry.service_type like 'SIA/%'
Find the data collections that are not linked to any services.
select collections.service_name from registry collections
where not exists
(select services.service_name from registry services
where services.linked_resources like '% '+databases.id +' %')
(In practice I'd implement the linked resources as a join table, rather than concatentating them in a single element of the registry table, but I hope this gives the sense of what I'm asking for.) Received on 2003-09-23Z20:00:27