Abstract

The primary task of database design is to represent scientifically the source relational schema of the real world with a set of normalized relational schema (database schema), many theories and algorithms about it had been proposed. However, these algorithms haven't taken so much effect as expected, because up to now, one critical technique involved in them about the computation problems for the projection of functional dependencies onto attributes haven't been well solved, such that the consistency of data is hard to maintain when such operations as insert, delete or update are performed on them, thus lead to the fact that database schema can't represent the source schema faithfully. In this paper, a new theory of projection of functional dependencies onto attribute is studied. Some theorems on projection of function dependencies on attribute is proposed and algorithm based on these theorems is developed. These theory and algorithm will exert helpful and significant influences on the database model design.

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