SPECIAL ATTRIBUTES FOR DATABASE NORMAL FORMS DETERMINATION.

The article deals with the relational schemes defined on the reduced sets of functional dependencies divided into equivalence classes. The concepts of non-essential and recoverable attributes are introduced, and the algorithms for their computing are proposed. Some properties of schemes, based on these attributes, are presented as well. Based on non-essential and recoverable attributes some conditions are introduced to make a relation be in the third or Boyce-Codd normal form. These conditions are just sufficient, because there could be a scheme that is in third or Boyce-Codd normal form but doesn't satisfy them. In addition, the article suggests a normalization algorithm that takes into account these conditions. [ABSTRACT FROM AUTHOR]