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Querying fuzzy relational databases through fuzzy domain calculus
Author(s) -
Galindo José,
Medina Juan Miguel,
Aranda Mª Carmen
Publication year - 1999
Publication title -
international journal of intelligent systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.291
H-Index - 87
eISSN - 1098-111X
pISSN - 0884-8173
DOI - 10.1002/(sici)1098-111x(199904)14:4<375::aid-int3>3.0.co;2-k
Subject(s) - relational calculus , codd's theorem , relational algebra , fuzzy logic , relational database , tuple , computer science , relational model , conjunctive query , mathematics , algebra over a field , calculus (dental) , artificial intelligence , database , discrete mathematics , pure mathematics , medicine , dentistry
In this paper we present a definition of a domain relational calculus for fuzzy relational databases using the GEFRED model as a starting point. It is possible to define an equivalent fuzzy tuple relational calculus and consequently we achieve the two query language levels that Codd designed for relational databases but these are extended to fuzzy relational databases: Fuzzy relational algebra (defined in the GEFRED model) and the fuzzy relational calculus which is put forward in this paper. The expressive power of this fuzzy relational calculus is demonstrated through the use of a method to translate any algebraic expression into an equivalent expression in fuzzy domain relational calculus. Furthermore, we include a useful system so that the degree to which each value has satisfied the query condition can be measured. Some examples are also included in order to clarify the definition. ©1999 John Wiley & Sons, Inc.