Collaboration on Source Catalogue DM, ADQL and SkyNodes

[Mark Taylor]

On Wed, 21 Dec 2005, Jim Gray wrote:

> Being a database guy... I assume they are everywhere.  :)
> 
> In general the cross match is not just spatial, 
> it also has predicates on the "vital signs" like magnitude and
> morphology. 
> And there are inner and outer joins and ... 

sure, STIL does those too, I was simplifying a bit for brevity.

> So,  my guess is that the data needs to have a schema and ...
> But.... I understand that if someone is building a portable client-side
> tool the "database" might be more like SleepyCat than MySQL or MsAccess.

What my algorithm sees is much less like a database than 
Berkeley DB/Sleepycat; for instance the tables to be matched may not
exist in any persistent form, but only as data structures in memory 
(though for large tables it's likely to be on disk somewhere).
But in the sense that it's working with a notional array of rows 
of values, with some columns which are marked as relevant to the
crossmatching, you can call it a database if you like :-).

Mark

-- 
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/