What is does the term key field mean in relation to database?

The key field is a unique field that identifies a specific data set. A key field frequently used for customer databases is a telephone number, because the phone number is unique to that particular customer. The key field is required to link various records with each other and for helping to normalize a database.
The key field is a unique field that identifies a specific data set. A key field frequently used for customer databases is a telephone number, because the phone number is unique to that particular customer. The key field is required to link various records with each other and for helping to normalize a database.