A partial dependency occurs when a non-key attribute depends on part of a candidate key. In which normal form is this condition eliminated?

• A. 3NF
• B. 2NF
• C. BCNF
• D. 1NF

Answer: (B)

The test is about removing partial dependencies, which happen when a non-prime attribute depends on just part of a composite candidate key. When you have a composite key (for example, StudentID and CourseID together as the key), a non-prime attribute like StudentName that depends only on one part (StudentID) is a partial dependency. The way to eliminate this is to move to the second normal form. In 2NF, every non-prime attribute must be fully functionally dependent on the entire candidate key, so you decompose the table so that each attribute’s value is determined by the whole key rather than part of it. A typical result is splitting into a Student table (StudentID, StudentName) and an Enrollment table (StudentID, CourseID, Grade), so no non-prime attribute depends only on part of a composite key.

Higher normal forms address other types of dependencies (transitive dependencies for 3NF, determinant rules for BCNF), and 1NF is simply about atomic column values.