Null Queries with Compound Fuzzy Attributes
Shyue-Liang Wang* and Yu-Jane Tsai**
*Department of Information Management I-Shou University, Kaoshiung, Taiwan, R.O.C. 1, Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung, Taiwan 84008, R. O. C
**National University of Kaohsiung in Preparatation No. 416, Lan-Chang road, Nan-Tzu District, Kaohsiung, Taiwan, R. O. C
We present a generalized approach for handling null queries that contain compound fuzzy attributes. Null queries elicit a null answer from the database. Compound fuzzy attributes are ambiguous attributes not defined in the original database schema but derived from multiple rigid attributes in a schema. Compound fuzzy attributes derived from simple numbers were studied by Nomura11). We extend compound fuzzy attributes so they can be derived from numbers, interval values, scalars, and sets of all these data types. Database management systems that handle this type of ambiguous attributes in null queries both reduce occurrences of null answers and provide an improved user-friendly query environment.