One important theory developed for the relational model involves the notion of functional dependency (fd). Like constraints, functional dependencies are drawn from the semantics of the application domain. Essentially, fd’s describe how individual attributes are related. Functional dependencies are a kind of constraint among attributes within a relation and that have implications for “good” relational schema design. Here we will look at:
- basic theory and definition of functional dependencies
- methodology for improving schema designs (normalization)
The aim of studying this is to improve understanding of relationships among data and to gain enough formalism to assist practical database design.