Design of relational database schemas : the traditional dependencies are not enough

Hitherto, most relational database design methods are based on functional dependencies (FDs) and multivalued dependencies (MVDs). Full mappings are proposed as an alternative to FDs and MVDs. A mapping between any two sets, apart from being one-one, many-one, or many-many, is either total or partial on the source and target sets. An 'into' mapping on a set, expresses the fact that an element in the set may not be involved in the mapping. An 'onto' mapping on a set is total on the set. A many-many (into,onto) mapping from set A to set B is written as A[sup=i] m----n B[sup=o]. The mappings incorporate more semantic information into data dependency specification. It is shown, informally, that the full mappings are more expressive than FDs and MVDs. Transformation rules, to generate Boyce-Codd normal form and projection-join normal form schemas from the full mappings, are defined. The full mapping/transformation rules provide a discipline for modeling nonfunctional relationships, within a synthetic approach.Science, Faculty ofComputer Science, Department ofGraduat