Research On The Paraconsistent Database

With the development of database technology, the application of databases is wider and wider and the data in database is more and more complicated. Incomplete information and inconsistent information are extremely common in real life. The traditional database based on classical 2-valued logic fails to manage these two kinds of information. Paraconsistent database, which based on 4-valued paraconsistent logic and relational data model, can effective manipulate two kinds of uncertain information. Therefore, research on paraconsistent database is important to theory of database as well as application of data processing. First, in this paper, a paraconsistent relational data model and its algebraic operators are introduced briefly. Then, paraconsistent relational calculus based on this model is discussed and domain relational calculus for paraconsistent database is presented. Second, after introduction of infinite relations on paraconsistent database, new method of extension of tuple has been developed based on particularity of algebraic operators in paraconsistent relations. Third, integrity restriction, data dependency and normal form on paraconsistent database have been established. Finally, we established two data models based on the improvement of paraconsistent relation. Paraconsistent relation model with membership, by introducing the concept of membership degree in fuzzy database, has strengthen the ability of handling inconsistent information on the paraconsistent relation. Negative disjunctive paraconsistent relation model introduces the concept of disjunctive tuples. Thus the ability of handling indefinite information has been intensified. At the time of establishing two data models, we have redefined the set operators and relation operators accordingly.