Comprehensive Metadata Query Interface for Heterogeneous Data Archives Based on Open Source PostgreSQL ORDBMS

TL;DR

This paper presents a PostgreSQL-based system for comprehensive querying of XML metadata in heterogeneous data archives, enabling efficient search and retrieval of characterisation data for astronomical archives.

Contribution

It introduces a novel metadata query service using PostgreSQL's XML support, with two access methods translating queries into XPath and XQuery for astronomical data archives.

Findings

Prototype implemented for ASPID-SR archive.

Supports direct translation of queries into XPath and XQuery.

Enhances search capabilities over complex XML metadata structures.

Abstract

We use PostgreSQL DBMS for storing XML metadata, described by the IVOA Characterisation Data Model. Initial XML type support in the PostgreSQL has recently been implemented. We make heavy use of this feature in order to provide comprehensive search over Characterisation metadata tree. We built a prototype of the Characterisation metadata query service, implementing two access methods: (1) HTTP-GET/POST based interface implements almost direct translation of the query parameter name into XPath of the data model element in the XML serialisation; (2) Web-Service based interface to receive XQuery which is also directly translated into XPath. This service will be used in the ASPID-SR archive, containing science-ready data obtained with the Russian 6-m telescope.