Functional Dependency. Presenter Usman Saeed. Definition. Definition: constraints on relations() characteristic of an attribute where values are determined by another attribute’s values A B if “for every valid instance of A, that value of A uniquely determines the value of B”
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A B if “for every valid instance of A, that value of A uniquely determines the value of B”
elements of that domain are indivisible
Example: A set of names is a non atomic value.
A relation is in second normal form if it is in first normal form AND every nonkey attribute is fully functionally dependant on the primary key.
Hence the table in my example is in violation of this rule because we have two rows for the same movie.
This can be rectified by making separate tables for
Genre and Actors.