[TAP] data type for column metadata

[Douglas Tody]

On Wed, 1 Apr 2009, Roy Williams wrote:

> -- Can we develop a set of Use Cases that a compliant IVOA TAP protocol is 
> built to be able to handle? Documentation of each can show how to solve 
> these.

This would be especially useful for ADQL, e.g., examples of common
queries using the spatial primitives.  Do we have anything like this
already?

> -- What does the standard say about authentication? What can be done without 
> authentication and what is the transition experience?

None of the DAL protocols (and registry etc.) have ever required
authentication.  This is supposed to be an optional advanced capability
of the service implementation (but I guess Roy just wants us all to
confirm this).

> -- What does "upload" mean for a table? Permanent URL or just 
> read-and-delete?

Since the reference is given each time the service is invoked why
should it matter?  The table referenced with UPLOAD needs to be there
when the service operation is invoked.  If UPLOAD is used, a service
could conceivably cache the upload table.  If inline uploads are
used clearly the table is used and discarded.  If/when we get vospace
integration into TAP then it will be possible to persist user tables
at the service.

 	- Doug