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Paper: The XCATDB: a Complex Database Based on Saada
Volume: 376, Astronomical Data Analysis Software and Systems XVI
Page: 699
Authors: Motch, C.; Michel, L.; Pineau, F.X.
Abstract: The Survey Science Center (SSC) of the XMM-Newton satellite provides a public interface to the European Photon Imaging Counter (EPIC) source catalogs implementing cross-correlations between EPIC X-ray sources and archival astronomical catalogs. These cross-correlations are computed by the Archival Catalog Database Subsystem (ACDS), developed in Strasbourg, as part of the automatic pipeline processing. A first release of this database (the XCATDB) based on an obsolete OODBMS was made public with the 1st XMM-Newton catalog in 2003. A new system, based on Saada, will be made public at the time of the 2nd release of the catalog in late 2006. Saada is well-suited to host heterogeneous data and especially to manage persistent relationships. This last feature is used to implement in a static manner the correlations computed by the ACDS. The Saada query language (SaadaQL) can express very complex constraints and can select X-ray sources using conditions on the patterns formed by the correlation links. SaadaQL also supports constraints based on Unified Content Descriptors (UCDs) allowing selections on multiple catalogs. The demonstration includes a presentation of the XCATDB prototype and is focused on the SaadaQL features and the use of UCDs to handle heterogeneous datasets.
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