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Paper: User Defined Functions for the ISO POST Mission Archive
Volume: 172, Astronomical Data Analysis Software and Systems VIII
Page: 249
Authors: Wieprecht, Ekkehard; Vandenbussche, Bart; Wiezorrek, Erich; Steinle, Helmut; Bauer, Otto H.; Arviset, Christophe; Hernandez, Jose; Plug, Arno M.; Saxton, Richard
Abstract: A major problem with designing archives in astronomy is defining the data resolution. In most cases, the smallest element in an archive is the object ``observation''. Attributes of this object contain meta-information about the observation that should be quickly queriable and are thus stored in the database engine. The data from the observation are stored external to the database engine as one big object. During the design of the archive, it is often difficult or even impossible to anticipate what meta-information of an observation should be queriable. We present a solution for this problem as adopted for the Post Mission Archive of the Infrared Space Observatory (ISO) mission. Expert users can create User Defined Functions (UDFs) that extract virtual attributes from files external to the database engine. These virtual attributes can then further be used in queries inside the database engine. We discuss the concept of User Defined Functions, system design, and implementation.
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