Công Thức Suy Dẫn Trong Mô Hình Dữ Liệu Dạng Khối

Abstract

-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.

Some properties of multivalued positive Boolean dependencies in the database model of block form

“…Definition 1.7 (4) Let block scheme α = (R, F), R = (id; A 1 , A 2 ,..., A n ), Fis the set of functional dependencies on R, K ⊆ ∪ n i=1 id (i) . K called a key of block schema α if it satisfies two conditions:…”