Efficiency increase of fuzzy query languages by using indexes for selected operations

The relatively weak performance of fuzzy database management systems is a major reason for the clear lack of commercial variants. A very important component of a database management system is the query language whose performance is improved amongst others by using indexes. Consequently, the applicability of indexes, designed for the management of fuzzy data, for several operations of a fuzzy query language, in particular a fuzzy equi-join and a fuzzy projection, is examined in this paper. In doing so, the advantages achieved with the integration of a specific index are compared with the benefits resulting from the utilization of a fuzzy equality indicator which is another approach for the efficiency increase of fuzzy query languages. The results will demonstrate that the use of an index can definitely enhance the performance of a fuzzy query language.