The Free On-line Dictionary of Computing (30 December 2018):

decision support database

   A database from which data is extracted and analysed
   statistically (but not modified) in order to inform business
   or other decisions.  This is in contrast to an operational
   database which is being continuously updated.

   For example, a decision support database might provide data to
   determine the average salary of different types of workers,
   whereas an operational database containing the same data would
   be used to calculate pay check amounts.

   Often, decision support data is extracted from operation
   databases.

   (1995-02-14)