March 2022
Intermediate to advanced
682 pages
22h 58m
English
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6.7 Higher Normal Forms
Although many database designs use 3NF or BCNF as their final stage, there are higher normal forms. These forms were developed to address additional types of defects or new information needs. They are described briefly here, but more details can be found at go.jblearning.com/Ricardo4e.
Fourth Normal Form: This form describes a type of dependency called a multivalued dependency that can exist between attributes. A relation in fourth normal form (4NF) has no such dependencies.
Definition: Let R be a relation having attributes or sets of attributes A, B, and C. There is a multivalued dependency of attribute B on attribute A if and only if the set of B values associated with a given A value is independent of the C values ...
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