Summary: March 23, 2008 DB:Functional Dependency 1
Functional Dependency
March 23, 2008 DB:Functional Dependency 2
Objectives
Definition of FD +
Inference Rules for Functional Dependency (FD)
Types of FDs +
March 23, 2008 DB:Functional Dependency 3
- Definition of FD ...
Describes the relationship between attributes in a relation.
For example, if A and B are attributes of relation R, B is
functionally dependent on A (denoted A B), if each value of A
in R is associated with exactly one value of B in R.
Functional dependency is a property of the meaning or semantics
of the attributes in a relation.
The determinant of a functional dependency refers to the attribute
or group of attributes on the left-hand side of the arrow.
Diagrammatic representation.
March 23, 2008 DB:Functional Dependency 4
... - Definition of FD ...

Source: Adam, Salah - Department of Information and Computer Science, King Fahd University of Petroleum and Minerals

Collections: Computer Technologies and Information Sciences