In relational databases, functional dependency is a concept that defines a relationship between two sets of attributes in a table. It is an essential concept in database normalization, helping to ensure data consistency and reduce redundancy. Functional dependencies form the basis for defining normal forms, which help organize data efficiently within a database.

Definition of Functional Dependency

A functional dependency, denoted as X → Y, exists between two sets of attributes X and Y if, for every unique value of X, there is a corresponding unique value of Y