[TAP] Summary: data type for column metadata
rplante at poplar.ncsa.uiuc.edu
Thu Apr 16 08:21:19 PDT 2009
Hi type enthusiasts,
Thanks, Pat, for the summary and calling for questions. My interest, of
course, is in adapting VODataService accordingly.
On Wed, 15 Apr 2009, Patrick Dowler wrote:
> 1. use ADQL datatypes rather than VOTable datatypes:
> BOOLEAN, SMALLINT, INTEGER, BIGINT,
> REAL, DOUBLE,
> VARCHAR, VARBINARY,
> POINT, REGION
I like this list. I think we also need to include a recommendation (at
least) for how these should be mapped to VOTable types. This is not only
for consistency in TAP responses, but also for describing a table
in the registry outside the context of TAP (e.g. describing the table
returned from an SIA query). Does this seem reasonable?
ADQL type VOTable
TIMESTAMP char arraysize="*", (format?)
(or is it numeric?)
VARCHAR char arraysize="*"
VARBINARY char arraysize="*", format not specified
POINT char arraysize="*", STC/s format
REGION char arraysize="*", STC/s format
We could get away with making this mapping only a recommendation if the
SCHEMA and/or VODataService description indicated the mapping.
> 2. add single additional optional metadata coordinate system spec
I like the idea of relying on the existing solution available in VOTable
using GROUPs and ucds/utypes. Of course, it would be good to capture this
in the registry description via VODataService. May I propose adapting the
GROUPs model into VODataService. Flatter structures makes searching
easier so it probably would look exactly like it.
I sense some consensus on these two questions so far. I would like to
immediately turn this around into a VODataService proposal. May I enlist
the respondants to Pat's summary for consultation on this proposal? (So
far, this has been Pat, Gerard, Markus, and Mark.)
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