The functional dependency is a relationship that exists between two attributes. It typically exists between the primary key and non-key attribute within a table.
The left side of FD is known as a determinant, the right side of the production is known as a dependent.
Assume we have an employee table with attributes: Emp_Id, Emp_Name, Emp_Address.
Here Emp_Id attribute can uniquely identify the Emp_Name attribute of employee table because if we know the Emp_Id, we can tell that employee name associated with it.
Functional dependency can be written as:
We can say that Emp_Name is functionally dependent on Emp_Id.
Types of Functional dependency
1. Trivial functional dependency
2. Non-trivial functional dependency