What is TAP?

TAP is a service protocol for accessing database, table data and table metadata (Dower et al., 2010). This protocol includes support for multiple query languages, including the Astronomical Data Query Language (Ortiz et al., 2008) based on the the Structured Query Language (SQL). It also includes support for both direct download (or synchronous) and delayed download for bigger queries (or asynchronous). Special support is provided for spatially indexed queries using the spatial extensions in ADQL. A multi-position query capability permits queries against an arbitrarily large list of astronomical targets, providing a simple spatial cross-matching capability. TAP was adopted by the International Virtual Observatory Alliance more than 10 years ago. An extension to TAP, called TAP+, adds more capabilities like authenticated access, persistent user storage area or management of asynchronous execution of jobs based on the Universal Worker Service or UWS (Harrison and Rixon, 2016).

For many years now, TAP/TAP+ based servers have been implemented across the archives of the European Space Agency to serve data and metadata to the worldwide scientific community (more than 10,000 scientists every month). And it does not only concern astronomy archives like the popular GAIA and XMM archives. TAP servers are also heavily used in the field of Heliophysics including ESA/NASA Solar Orbiter, ESA Cluster, CNSA/ESA Double Star and ESA Proba-2 mission archives. In the field of planetary physics, a modified version of the TAP protocol is used, called Europlanet TAP protocol or EPN-TAP, implemented in the Planetary Science Archive or PSA. 

In other words, the Table Access Protocol can be considered as a standard at the ESAC Science Data Centre, with strong heritage and on-going maintenance and development. After evoking TAP main functionalities, we will present TAP queries examples from the SOHO TAP server that hosts data and metadata. For every example, we will provide the same example using the old SAIO command line subsystem. 

Dower, P., G. Rixon, D. Tody, Table Access Protocol version 1.0, International Virtual Observatory Alliance document, 2010;  https://doi.org/10.5479/ADS/bib/2010ivoa.spec.0327D
Harrison, P.A. and G. Rixon, Universal Worker Service Pattern, Version 1.1, IVOA Recommendation 24 October 2016; https://doi.org/10.5479/ADS/bib/2016ivoa.spec.1024H
Ortiz, I., J. Luster, P. Dowler, IVOA Astronomical Data Query Language Version 2.0, 2008; https://doi.org/10.5479/ADS/bib/2008ivoa.spec.1030O