Which normal form removes partial dependency ?

Concept: In relational database normalization, each higher normal form removes one specific class of dependency. Second Normal Form (2NF) requires a relation to already satisfy 1NF, and additionally requires that every non-prime attribute be fully functionally dependent on the whole of every candidate key -- not on just part of a composite key. A non-prime attribute depending on only part of a composite candidate key is called a partial dependency, and eliminating it is exactly what the 1NF-to-2NF transformation does.

Application: A partial dependency can only arise when a candidate key is composite (made of more than one attribute); with a single-attribute key, every non-prime attribute is automatically dependent on the whole key. Converting a 1NF relation to 2NF means decomposing it so that any attribute depending on only part of the composite key is moved into its own relation keyed on that part, leaving every remaining non-prime attribute dependent on the whole key -- this decomposition is precisely what removes the partial dependency.

Cross-check (contrast with the other normal forms):

• 1NF only requires that every column hold a single atomic value and that there be no repeating groups; it does not analyze functional dependency between the key and non-key attributes at all, so it has no mechanism to remove partial dependency.

• 3NF builds on 2NF by removing transitive dependency -- the case where a non-prime attribute depends on another non-prime attribute rather than directly on the key -- which is a different dependency class from partial dependency.

• BCNF strengthens 3NF by requiring every determinant of a functional dependency in the relation to be a superkey (a candidate key or a superset of one), which addresses anomalies from overlapping candidate keys rather than partial dependency specifically.

Since partial dependency is defined as a non-prime attribute depending on only part (not all) of a composite candidate key, and only the 2NF definition explicitly targets and removes this dependency, the normal form that removes partial dependency is 2NF.