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

Transitive Dependency

An indirect dependency in which a non-key attribute depends on another non-key attribute rather than directly on the key.

Definition

If A -> B and B -> C, where A is the key and B is not a key, then C is transitively dependent on A. Moving B and C into their own table removes the dependency and achieves 3NF.

Example

OrderID -> CustomerID -> CustomerCity in an Orders table.

Exam tip

If a non-key column can be looked up from another non-key column, the table violates 3NF.

Related terms