A fuzzy bag is a bag in which each occurrence of an element is associated with a grade of membership. This notion can be viewed as a generalization of the concepts of set, fuzzy set and bag. The set of fuzzy integers (Nf ) provides a general characterization in which all these different concepts are treated in a uniform way and can then be composed. In the field of databases, the use of fuzzy b...

The aim of this paper is to give guidelines on how to formalize fuzzy relational database queries using 1 2 LΠ fuzzy logic. After the short introduction, we give an overview of the 1 2 LΠ logic. In the continuation we give a brief overview of the FRDB queries and query-database similarity relation. We conclude the paper with the description of FRDB query formalization using presented definitions.

Fuzzy set theory has been extensively applied to extend various database models and resulted in numerous contributions, mainly with respect to the popular relational model or to some related form of it. To satisfy the need of modeling complex objects with imprecision and uncertainty, recently many researches have been concentrated on fuzzy semantic (conceptual) data models. This paper reviews f...

Most query languages are designed to retrieve information from databases containing precise and certain data using precisely specified commands. Application of fuzzy set theory to relational data models has been studied extensively in recent years. This paper presents a calculus for fuzzy queries on a fuzzy entity-relationship model. The paper, first, defines a fuzzy entity-relationship model c...

We provide uniform and invertible logical rules in a framework of relational hypersequents for the three fundamental t-norm based fuzzy logics i.e., Łukasiewicz logic, Gödel logic, and Product logic. Relational hypersequents generalize both hypersequents and sequents-of-relations. Such a framework can be interpreted via a particular class of dialogue games combined with bets, where the rules re...

The theory of fuzzy sets has been recognized as a suitable tool to model several kinds of patterns that can hold in data. In this paper, we are concerned with the development of a general model to discover association rules among items in a (crisp) set of fuzzy transactions. This general model can be particularized in several ways; each particular instance corresponds to a certain kind of patte...

In this paper we deal with the problem of treating with dependencies in relational databases which do not hold in an exact manner as classical functional dependencies but in a weaker sense, i.e., we face with relations which satisfy dependencies such that `people with similar age and height have similar weight'. We model this relationship through the concept of fuzzy dependency. We see that the...

As main result of all our previous work we have now available a FSQL Server for Oracle Databases pro grammed in PL SQL This server allows us to query either a Fuzzy or Classic Relational Database with the FSQL language Fuzzy SQL The FSQL language is an extension of the SQL language which permits us to write exible or fuzzy conditions in our queries to a fuzzy or traditional database In this wor...