A PROBABILISTIC RELATIONAL MODEL AND ALGEBRA

Although the relational model for databases provides a great range of advantages over other data models, it lacks a comprehensive way to han dle incomplete and uncertain data. Uncertainty in data values, however , is pervasive in all real-world environments and has received much at tention in the literature. Several methods have been proposed for inco rporating uncertain data into relational databases. However, the curre nt approaches have many shortcomings and have not established an accep table extension of the relational model. In this paper, we propose a c onsistent extension of the relational model. We present a revised rela tional structure and extend the relational algebra. The extended algeb ra is shown to be closed, a consistent extension of the conventional r elational algebra, and reducible to the latter.