Topics: Database

In databases, a superkey is a set of attributes that uniquely identify each tuple in a relation. In other words, a superkey defines a functional dependency between it and the rest of the attribute values in a given tuple.

A superkey can also be seen as a set of attributes that have a unique combination of values in each row.

Logically, tuples with the same superkey must also have the same non-key attribute values.

The minimal superkey is called a candidate key.