-The report proposes the formula derived concepts in the database model of block form, speech and prove some properties of the formula derived, property of the closed sets and the truth block in the block diagram, the conditions necessary and sufficient for the truth block of a derived assembly, construction assembly derived algorithm get a binary block as the truth block ...In addition, the necessary and sufficient condition for a Boolean formula can be expressed through a derived assembly has also been stated and proven here.

No abstract

At the present time, some types of database models are considered, in which three types of database models are objects of interest: Hierachiral model, Network model and Relational model. This paper introduces a new model for databases, which called a database model of block form. Some basis concepts and block form-relational algebra are introduced for this model. Some of properties related to keys of block schema and blo'ck form-relational algebra are claimed and proved. It is shown that the relational database model is special case of the database model of block form in which each relation is a block with the index set, containing only one element.

No abstract

The report proposed the concept of multivalue positive Boolean dependencies in the database model of block form, proved the sufficient properties of the functions I,  and , equivalence of three types derived: logically m-derived, m-derived by block, m-derived by block not exceeding two elements, the necessary and sufficient criteria of the tight expression for the set of multivalue positive Boolean dependencies... In addition, the properties related to this concept while the block degenerate into relationship has been stated and proved here.