______________ is the superset of all keys in a relation.OptionsSuper keyCandidate keySub keyForeign key

Understanding the Concepts

In the context of relational databases, keys are essential for identifying records uniquely within a table (relation).

1. Super Key: A super key is a combination of one or more attributes that can uniquely identify a record in a relation. This means any combination that can identify rows, whether it has additional attributes or not, qualifies as a super key.

2. Candidate Key: This is a minimal super key, meaning it has no unnecessary attributes. A candidate key is a potential key which may serve as the primary key.

3. Sub Key: This term is not standard in database terminology.

4. Foreign Key: A foreign key is an attribute or a set of attributes in one table that refers to the primary key in another table, establishing a relationship between the two.

Final Answer

Super key is the superset of all keys in a relation. It includes all possible combinations of attributes that can uniquely identify records, which encompasses candidate keys, among others.