## Fuzzy Loss Less Decompositions in Databases (1997)

Citations: | 6 - 5 self |

### BibTeX

@TECHREPORT{Cubero97fuzzyloss,

author = {J. C. Cubero and J. M. Medina and O. Pons and M. A. Vila},

title = {Fuzzy Loss Less Decompositions in Databases},

institution = {},

year = {1997}

}

### OpenURL

### Abstract

In this paper we deal with the problem of defining projection and join operators in the framework of a fuzzy relational database. We study the properties of such an operators relating to the concept of fuzzy functional dependency. There are two main properties to achieve: On the one hand, if a relation r satisfies a dependency between two sets of attributes, X and Y , then we want to preserve this dependency in the fuzzy projection over XY of r. On the other hand, we want to test a fuzzy dependency just by looking at this projection. Therefore, such a projection operator must allow us to store the information conveyed in r into a separate relation with fewer tuples. In order to define the criterion for fuzzy dependency, we shall need to extend a resemblance relation defined for crisp data to the fuzzy case. Finally, we shall introduce a fuzzy join operator which will allow us to recover the information given in a relation, from its projections 1 . Keywords: Fuzzy Functional Dependen...