Lossless join property in fuzzy relational databases. (English) Zbl 0805.68033

Summary: To answer users’ queries in a fuzzy relational database, it often becomes necessary to decompose a relation scheme into components and subsequently to perform the join operation of two or more component fuzzy relation. For maintaining database integrity, it is essential that the join operation of the components yield the original relation. Such a decomposition is termed a lossless join decomposition. However, the join may not always recover the original relation. In this paper, we study the decomposition problem of fuzzy relation schemes. The associated question of lossless join is also investigated. It has been proved that the algorithm proposed by G. Loizou and P. Tanisch [Inf. Syst. 8, 25-27 (1983; Zbl 0514.68089)] to test lossless join property for classical relations is applicable to examine lossless join of fuzzy relations in the presence of the fuzzy functional dependencies.


68P15 Database theory


Zbl 0514.68089
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