How do you spell Hannukah?
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.