thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Data & Analytics · Intermediate

Partial Dependency

A dependency in which a non-key attribute depends on only part of a composite primary key.

Definition

Partial dependencies cause redundancy because the dependent value repeats for every combination with the other key part. Removing them is what achieves 2NF.

Example

With key (StudentID, CourseID), StudentName depends only on StudentID.

Exam tip

Partial dependency is a 2NF problem; transitive dependency is a 3NF problem.

Related terms