In this paper,based on probabilistic and cognitive uncertainties,we set up an uncertain database model and presented the uncertain relational algebra ,and proved that the uncertain normal forms are closed under operat...In this paper,based on probabilistic and cognitive uncertainties,we set up an uncertain database model and presented the uncertain relational algebra ,and proved that the uncertain normal forms are closed under operations of the uncertain relational algebra. At last ,we studied the semantics of the uncertain relation.展开更多
文摘In this paper,based on probabilistic and cognitive uncertainties,we set up an uncertain database model and presented the uncertain relational algebra ,and proved that the uncertain normal forms are closed under operations of the uncertain relational algebra. At last ,we studied the semantics of the uncertain relation.
