Generating Compound Attributes from Fuzzy Data for Null Queries

Abstract We present here an approach for handling null queries that contain compound attributes derived from fuzzy data. Null queries are queries that elicit a null answer from the database. Compound attributes are ambiguous attributes that are not defined in the original database schema but can be derived from multiple rigid attributes in schema. Compound attributes derived from simple numbers were studied by Nomura etc[8]. In [9,10], we extended the compound attributes to be derived from numbers, interval values, and scalars under a unified approach. In this work, we further extend compound attributes so that they can be derived from fuzzy sets of numbers, interval values, and scalars. Database management systems that can handle this type of ambiguous attributes in null queries not only can reduce the occurrences of null answers but also provide an improved user-friendly query environment.