What is alternate key and candidate key?

Is alternate key and candidate key same?

There can be multiple Super keys and Candidate keys in a table, but there can be only one Primary key in a table. Alternate keys are those Candidate keys that were not chosen to be the Primary key of the table. Composite key is a Candidate key that consists of more than one attribute.

What is alternate key example?

Select any one of the above key as Primary Key, for example, EmployeeSSN. The rest of the two keys would then be called Alternate Keys because they were candidates of Primary Key. Therefore, Employee_SSN and Employee_Phone are Alternate Keys.

What is alternate key for?

An alternate key is none other than a candidate key, so the use/role of an alternate key is the same. It means an alternate key is also used to identify those columns in a table that can uniquely identify all the records of the table.

What is candidate key 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.