What are Armstrong's Axioms in Functional Dependency in DBMS?Armstrong axioms are a complete set of inference rules or axioms, introduced and developed by William W. Armstrong in 1974. The inference rules are sound which is used to test logical inferences of functional dependencies. The axiom ...
DBMS Functional Dependency MCQs: This section contains multiple-choice questions and answers on functional dependency in DBMS. Submitted byAnushree Goswami, on March 31, 2022 1. Two attributes can be functionally ___ on/of each other. Dependent ...
The dependency of an attribute on a set of attributes is known as trivial functional dependency if the set of attributes includes that attribute. Symbolically: A ->B is trivial functional dependency if B is a subset of A. The following dependencies are also trivial: A->A & B->B For exam...
According to the analysis of existing complicated functional dependencies constraint,we conclude the conditions of defining functional dependency in XML,and then we introduce the concept of the node value equality. A new path language and a new definition of functional dependencies in XML(XFD) are ...
3.1.1DefinitionofFD-pp68Section3.1.1 LetRbearelationschemeandX,YbesetsofattributesinR. AfunctionaldependencyfromXtoYexistsifandonlyif: Foreveryinstanceof|R|ofR,iftwotuplesin|R|agreeonthevaluesoftheattributesinX,thentheyagreeonthevaluesoftheattributesinY ...
We describe an algorithm to test whether a multivalued dependency is implied by a set of functional and join dependencies. The worst case running time of the algorithm is O ( nm ), where n is the length of the input and m is the number of the attributes in the universe. We also ...
Functional dependency is also a property of relational schema "R" and not a particular legal relation "r" of "R".Now let us consider, a relational "a" schema "R" and let "x" and "y" be the two set of attributes, now there is a functional dependency from "x" to "y"...