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In this paper there is proposed a method of partition the attributes of relation scheme in equivalence classes and in nonre-dundant equivalence classes. Several properties of these equivalence classes are proved. Their properties serve as the basis for an algorithm with a polynomial complexity, which determines the prime attributes of a database schema.
The paper proposes a problem decomposition method for building optimal cover for a set of functional dependencies to decrease the solving time. At the beginning, the paper includes an overview of the covers of functional dependencies. There are considered definitions and properties of non redundant covers for sets of functional dependencies, reduced and… (More)
The present paper is concerned with list processing in Turbo Prolog language. It doesn't claim to be an exhaustive description of operations which can be performed upon lists. Nevertheless adduced programs are most representative, more or less known to specialists in logic programming domain. By means of examples are explained the list manipulation… (More)
The general scheme of a system for a conceptual and logical database design is described. The database management systems, becoming a convenient way of creating a database, are frequently used as a new mode of access to data, but not as a means of common possession of them. This is due to the great importance of database structure. The principal… (More)
In this paper, based on equivalence classes of attributes there are formulated necessary and sufficient conditions that constraint a database schema to be in the second, third or Boyce-Codd normal forms. These conditions offer a polynomial complexity for the testing algorithms of the normalizations level.