ABSTRACT: Despite the widespread use of relational database management systems, their decision support capabilities have been limited. These limitations include: (1) very limited support for expression of general statements and exceptions, (2) limited capabilities for what-if analysis, and (3) problems with the way derived data is handled. This paper shows that additional power can be placed in relational database systems via a new construct called Derived Relations with Exceptions (DRES). DRES are a superset of relational views that provide greater decision support capabilities in that they handle exceptions to general rules and can operate in a hypothetical mode that provides an easier way to experiment with alternative scenarios in a what-if fashion. DRES are implemented by extending the SQL database language.
Key words and phrases: decision support systems, relational databases, database view modeling, SQL