On Tue, 24 Apr 2007, Pedro Osuna wrote:
> 7) Clarify point with Doug: in which forum is the getCapabilities
getCapabilities is introduced in SSAP and has been under discussion between DAL and Registry for some time. We have to finalize this for the SSAP WD shortly (I am working with Ray directly on this one; Ray will also join us in the DAL-1 session in Beijing to discuss this). We will want the same mechanism in all the DAL services. It returns only service metadata.
stageData is being actively discussed now between DAL and GWS (Guy). The mail I forwarded earlier summarizes what is planned, but we are still actively discussing this. We will want to implement stageData initially in both SIAV2 and (presumably) TAP.
There is also the getAvailability method, used to monitor service health and availability (discussion between DAL and GWS).
For TAP, the key issue would appear to be the scope of queryData, and whether this can be used as a uniform mechanism to return both table data and metadata (this does not mean we would have to permit ADQL for metadata queries). In the other DAL interfaces, it is used for discovery, to return dataset metadata, and to propose/plan data products (often virtual) which can be computed and returned. All of these functions return the query results as a table, hence it is reasonable to use the same mechanism to directly query a data table as well. In the simplest case of a queryData on a single data table, this reduces to what is essentially a cone search, but with a somewhat generalized set of input parameters, plus an ADQL option.