TABLE OF CONTENTS Information modeling in databases can be carried out at two different levels: conceptual data modeling and logical database modeling. Therefore, we have conceptual data models and logical database models for database modeling, respectively. Conceptual data models are generally used for information modeling at a high level of abstraction. However, information systems are constructed based on logical database models. So at the level of data manipulation, i.e., a low level of abstraction, logical database models are used for information modeling. Here, logical database models are often created through mapping conceptual data models into logical database models. This conversion is called conceptual design of databases.
There have been several proposals for extending relational database model as well as nested relational database model in order to represent and query fuzzy data. Current efforts have been concentrated on fuzzy object-oriented databases and some related notions. Compared with the studies of the fuzzy database models, little work has been done in modeling imprecision and uncertainty in conceptual data model. It is particularly true in developing design methodologies for implementing fuzzy databases. To fill this gap, this chapter proposes the conceptual designs of the fuzzy nested relational databases using the fuzzy EER model and the fuzzy object-oriented databases using the fuzzy UML model. Also the mapping of the fuzzy XML model into the fuzzy relational database model is investigated in this chapter.
The transformations of the fuzzy ER...
