What are the different types of functional dependency in databases?

What are the different types of functional dependency in databases?

Functional dependency is a relationship between attributes in a database. The main types include: 1. Full Functional Dependency: When an attribute is functionally dependent on a whole primary key, not just part of it. 2. Partial Functional Dependency: When an attribute is dependent on part of a composite primary key. 3. Transitive Dependency: When an attribute depends on another attribute that is not a primary key. 4. Multivalued Dependency: When one attribute can have multiple values for a single value of another attribute.

Can you give an example of full functional dependency?

Sure! Consider a table with attributes: StudentID (primary key), StudentName, and Course. If StudentName is fully dependent on StudentID, it means for each StudentID, there is exactly one StudentName. This is a full functional dependency.

What about partial functional dependency?

In a table with a composite key, like (StudentID, CourseID), if StudentName depends only on StudentID, that's a partial functional dependency. It means StudentName is not dependent on the entire key.

How can transitive dependency affect database normalization?

Transitive dependency can lead to redundancy and anomalies in a database. To achieve normalization, you should eliminate transitive dependencies by creating separate tables for the dependent attributes.