Final answer:
To find the keys and superkeys of a relation, identify the minimal set of attributes for keys and add any other attributes for superkeys, ensuring uniqueness for both.
Step-by-step explanation:
To determine the keys and superkeys of a relation in a database, you need to understand the structure of the relation and the attributes it contains. Keys are a concept in databases used to ensure that each record within a table is uniquely identifiable. A key is a minimal set of attributes that can uniquely identify a tuple in a relation. A superkey is a set of one or more attributes that, taken collectively, can uniquely identify a tuple in a table but may have additional attributes that are not necessary for the unique identification.
To find a key, look for the smallest subset of attributes that can uniquely identify each tuple in the relation. A key must satisfy two conditions: uniqueness and minimality. Uniqueness means no two distinct tuples can have the same key values, while minimality ensures that no attribute can be removed from the key without losing the uniqueness property.
To find a superkey, start with a key and then add any other attributes to it. Since the original key ensured uniqueness, adding more attributes will still maintain that uniqueness, hence creating a superkey. All keys are by definition also superkeys, but not all superkeys are keys because they might not satisfy the minimality condition.
In practical terms, the primary key and unique constraints in a database system help enforce the uniqueness of the keys. Additional indices might be defined on superkeys to enhance query performance.