Editing Functional dependency (section)

=== Employee department ===

A classic example of functional dependency is the employee department model. 

{| class="wikitable"
|-
! Employee ID !! Employee name !! Department ID !! Department name
|-
| 0001 || John Doe || 1 || Human Resources
|-
| 0002 || Jane Doe || 2 || Marketing
|-
| 0003 || John Smith || 1 || Human Resources
|-
| 0004 || Jane Goodall || 3 || Sales
|}

This case represents an example where multiple functional dependencies are embedded in a single representation of data. Note that because an employee can only be a member of one department, the unique ID of that employee determines the department.

* Employee ID → Employee Name
* Employee ID → Department ID

In addition to this relationship, the table also has a functional dependency through a non-key attribute

* Department ID → Department Name

This example demonstrates that even though there exists a FD Employee ID → Department ID - the employee ID would not be a logical key for determination of the department Name. The process of normalization of the data would recognize all FDs and allow the designer to construct tables and relationships that are more logical based on the data.