IVOA WG data access layer
Markus.Dolensky at eso.org
Fri Apr 4 05:23:31 PST 2003
It was mentioned before, but conceptually VOQL appears to be closer to
an extension of an SQL-kind of query language whereas DAL will deal with
- how to turn info harvested from a registry into a VOQL query
- how to perform transaction management of distributed queries
- error handling
Consequently, if VOQL returns tabular data then DAL has to have a method
to transfer it to a scratch space where the results from other sub
queries are assembled.
Tony Linde wrote:
> I think the DAL has to look at all types of access to data whether querying
> catalogues, accessing images, time series or spectra and any other type of
> data access.
> Or is the split intended to be:
> . VOQL addresses access to tabular data
> . DAL addresses access to non-tabular data
> Might work.
More information about the dal