Data and Information Management

This section provides a brief overview of fuzzy set approaches for database management and querying. Incompletely known information as well as flexible query handling capabilities are expected to extend the range of applications for future database management systems. The term fuzzy databases, which is extensively used in the specialized literature, covers several different meanings, which are reviewed. The use of a similarity measure as a fuzzy technique used to extend the relational data model is described, as well as the possibility-theory-based approach, which proves to be useful for representing imperfectly known data and soft constraints. Pattern matching is extended for handling this kind of datum by means of flexible queries. Related database issues, namely, functional dependencies and database security, are also discussed. Alternative fuzzy data models and other uncertainty management problems in databases are briefly mentioned in the conclusion.