User Defined Functions for the ISO Post Mission Archive
E. Wieprecht, B. Vandenbussche, E. Wiezorrek, H. Steinle, O.H.
Bauer,
C. Arviset, J. Hernandez, A.M. Plug and R. Saxton
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 of the observation is 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.
Keywords: ISO SWS: PMA Archive SQL
Status: ADA SS98 accepted
Address: mailto:
ewieprec@mpe.mpg.de
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