Community feedback re TAP metadata
yuji.shirasaki at nao.ac.jp
Thu Mar 8 02:35:00 PST 2007
Before describing my comments on the subject, I have to apologize that
I cannot attend today's telecon. I have a cold, so going back home to
Here are my opinions on TAP metadata:
1. I don't think TAP should define an interface to return the service metadata
and also it metadata structure. These things are related to the mechanism
to find a service that user wants to access, so they should be defined in the
I don't agree that the interface should be mandatory for TAP service.
We already have a path to register the metadata using the publishing
registry, that is enough. Why we need another way to register the metadata ?
And if many complex operations are defined, it will become more difficult for
service provider to imlement and maintain the service so that it correctly
reacts to the query.
I don't like to have two paths to expose the service metadata.
2. TAP should have an access mechanism to query the table/column information.
SQL is an approriate language for that purpose. All the relation DB has such
functionality. This should be a mandatory operation, since without these
information it is impossible to write a correct SQL. VOTable is enough for
retruned format. Tabular format is easy to use. Structure data is not easy
to use and also not easy to define.
It is better that these information is accessible directly from a TAP service
rather than from a registry. These inoformation is frequently refered by a client,
so I am afraied the registry becomes very busy if such important information is
centralized to the registry servcice.
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