Intro to Functional Dependencies

In this lesson, we will discuss the basic concepts of functional dependencies.

We'll cover the following


One important theory developed for the entity relational (ER) model involves the notion of functional dependency (FD). The aim of studying this is to improve your understanding of relationships among data and to gain enough formalism to assist with practical database design.

A functional dependency is a relationship between two attributes, typically the primary key (PK) and other non-key attributes within a table. For any relation R, attribute Y is functionally dependent on attribute X, if, for every valid instance of X, that value of X uniquely determines the value of Y. This relationship is indicated by the representation below :

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