Which of the following is known as minimal super key?Primary keyCandidate keyForeign keyNone

To answer the question regarding minimal super keys, let's analyze the options provided.

1. Primary Key: A primary key is a unique identifier for a record in a database table. It is a minimal super key by definition, as it uniquely identifies each row without any unnecessary attributes.

2. Candidate Key: A candidate key is also a minimal super key. It is a unique identifier among a set of attributes that can serve as a primary key. However, it is not as commonly referred to as just "minimal super key" since there can be multiple candidate keys in a table.

3. Foreign Key: A foreign key is used to establish a relationship between two tables and it references the primary key of another table. It is not considered a minimal super key.

4. None: This option implies that none of the above choices are minimal super keys, which is incorrect since both the primary key and candidate key can be minimal super keys.

Final Answer

The correct answer is Candidate key because it is defined as a minimal super key, which means it contains no unnecessary attributes beyond those needed to uniquely identify a row.