Table Access Protocol Applied to the SIMBAD Database

摘要

We have implemented in the SIMBAD service the Table Access Protocol (TAP), a standard of the Virtual Observatory defining a protocol for accessing astronomical catalogs and database tables using queries written in the Astronomical Data Query Language (ADQL), another VO standard. Implementing TAP requires several steps: the definition of a database schema with the data exposed to the users, the translation of ADQL queries into regular SQL language performing the queries in SIMBAD, and the implementation of the Universal Worker Service (UWS) standard to manage asynchronous queries, useful for long queries, either by their duration or their output size. These standards were implemented as much as possible in a generic way, allowing them to be reused in other services, as it has already been done in the database generator SAADA. The ADQL to SQL translator uses callbacks to implement the specific routines for a given service. All these libraries have been designed as autonomous packages, easy to reuse with very few specific developments. The whole development is in the Java language.