What is candidate key and example?

What is candidate key?

What is a Candidate key? Candidate key is a single key or a group of multiple keys that uniquely identify rows in a table. A Candidate key is a subset of Super keys and is devoid of any unnecessary attributes that are not important for uniquely identifying tuples.

What is super key and candidate key with example?

Super Key is an attribute (or set of attributes) that is used to uniquely identifies all attributes in a relation. Candidate Key is a subset of a super key. All super keys can't be candidate keys. But all candidate keys are super keys.

How do I choose a candidate key?

A candidate key is a subset of a super key set where the key which contains no redundant attribute is none other than a Candidate Key. In order to select the candidate keys from the set of super key, we need to look at the super key set.

What is candidate key in ER diagram?

A candidate key is selected by the designer to uniquely identify tuples in a table. It must not be null. A key is chosen by the database designer to be used as an identifying mechanism for the whole entity set. This is referred to as the primary key.