  With the success and widespread of the IVOA Table Access Protocol (1) for
discovering and querying tabular data in astronomy, more than one hundred of
TAP services exposing altogether 22 thousands of tables are accessible from the
IVOA Registries at the time of writing. Currently the TAP protocol presents
table data and metadata via a {TAP\_SCHEMA} describing the served tables with
their columns and possible joins between them. We explore here how to add an
information layer, so that values within table columns can be gathered and used
to populate instances of objects defined in a selected IVOA data model like
Photometry, Coords, Measure, Transform or the proposed MANGO container model.
This information layer is provided through annotation tags which tell how the
columns' values can be interpreted as attributes of instances of that model.
Then when a TAP query is processed, our server add-on interprets the ADQL query
string and produces on-the-fly, when possible, the TAP response as an annotated
VOTable document. The FIELD elements in the table response are mapped to
corresponding model elements templated for this service. This has been
prototyped in Java, using the VOLLT package library and a template annotation
document representing elements from the MANGO data model. This has been
exercised on examples based on Vizier and Chandra catalogs.
