What is candidate key and alternate key?

What is the alternate key?

Alternate keys are those candidate keys which are not the Primary key. There can be only one Primary key for a table. Therefore all the remaining Candidate keys are known as Alternate or Secondary keys.

What is candidate key?

A candidate key is a specific type of field in a relational database that can identify each unique record independently of any other data. Experts describe a candidate key of having "no redundant attributes" and being a "minimal representation of a tuple" in a relational database table.

What is candidate key and example?

Candidate Key: The minimal set of attributes that can uniquely identify a tuple is known as a candidate key. For Example, STUD_NO in STUDENT relation. The value of the Candidate Key is unique and non-null for every tuple. There can be more than one candidate key in a relation.

What is the difference between a candidate key and a secondary key?

Secondary Key is the key that has not been selected to be the primary key. However, it is considered a candidate key for the primary key. Therefore, a candidate key not selected as a primary key is called secondary key. Candidate key is an attribute or set of attributes that you can consider as a Primary key.