Modeling Fuzzy Data with Fuzzy Data Types in Fuzzy Database and XML Models

Various fuzzy data models such as fuzzy relational databases, fuzzy object-oriented databases, fuzzy objectrelational databases and fuzzy XML have been proposed in the literature in order to represent and process fuzzy information in databases and XML. But little work has been done in modeling fuzzy data types. Actually in the fuzzy data models, each fuzzy value is associated with a fuzzy data type. Explicit representations of fuzzy data types are the foundation of fuzzy data processing. To fill this gap, in this paper, we propose several fuzzy data types, including fuzzy simple data types, fuzzy collection data types and fuzzy defined data types. We further investigate how to declare the fuzzy data types in the fuzzy object-oriented database model and fuzzy XML Schema. The proposed fuzzy data types can meet the requirement of modeling fuzzy data in the fuzzy databases and fuzzy XML.