On the Theory of Relational Data Bases with Incomplete Information
In many applications the information stored in relational databases is incomplete. Database designers and users quite often face difficulties due to the inadequate consideration of incomplete information. In this paper we present a theory for the treatment of incomplete information in relational databases using L-relations and algebras of L-relations. We show that the main results of the theory of relational databases like the theory of functional and mulivalued dependencies remain valid for L-relations. Furthermore, it is shown that in order to solve the decomposition problem for L-relations we have to investigate systems of equations with coefficients in L which express specific properties of L-relations.
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