What Does Candidate Key Mean?
A candidate key is a specific type of field in a relational database that can identify each unique record independently of any other data.
Techopedia Explains Candidate Key
Candidate Keys and Primary Keys
The relationship of the candidate key and primary key is easier to describe — basically, a relational database can have more than one candidate keys, but only one of these candidate keys will be the primary key that will be primarily used to identify each record uniquely.
