Abstract
Objectives: The article proposed a new type of dependency on blocks and slices. Then found and proved the properties of this new dependency. Method: Logical inference methods were used. Findings: A new type of data relationship has been proposed: Multivalued positive Boolean dependencies on block and slice in the database model of block form. From this new concept, the article stated and demonstrated the equivalence of the three types of deduction, namely: m-deduction by logic, m-deduction by block, m-deduction by block has no more than two elements. Next are the necessary and sufficient criteria of the tight m-expression for the set of multivalued positive Boolean dependencies on block and slice, the sufficient properties for a set of functions fI;^;_g. The properties related to this new concept when the block degenerated into relation. Novelty: The proposed new dependency with their properties on the block and on the slice are completely new. Keywords: Multivalued positive Boolean dependencies; block; Boolean dependencies; block schemes
Highlights
IntroductionLet R = (id; A1, A2,..., An) is a finite set of elements, where id is non-empty finite index set, Ai
1.1 The block, slice of the blockDefinition 1 .1 (1)Let R = is a finite set of elements, where id is non-empty finite index set, Ai (i=1.. n) is the attribute
In the case id = {x}, the block degenerated into a relation and the above m-equivalence theorem becomes the mequivalent theorem in the relational data model
Summary
Let R = (id; A1, A2,..., An) is a finite set of elements, where id is non-empty finite index set, Ai N) there is a corresponding value domain dom (Ai). A block r on R, denoted r(R) consists of a finite number of elements that each element is a family of mappings from the index set id to the value domain of the attributes Ai Let R = (id; A1, A2,..., An), r(R) is a block over R. For each x ∈ id we denoted r(Rx) is a block with Rx = ({x}; A1, A2,..., An) such that: tx ∈ r (Rx) ⇔ tx =. R(Rx) is called a slice of the block r(R) at point x
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