In database theory, multivalued dependency is a full constraint between two sets of attributes in a relation.
In contrast to the functional dependency, the multivalued dependency requires that certain tuples be present in a relation. Therefore, a multivalued dependency is a special case of tuple-generating dependency. The multivalued dependency plays a role in the 4NF database normalization.
A multivalued dependency is a special case of a join dependency, with only two sets of values involved, i.e. it is a 2-ary join dependency.
Read more about Multivalued Dependency: Formal Definition, Example, Interesting Properties, Definitions
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