How To Software How to Identify a Database Record Using a Superkey A superkey is an attribute that can be used to identify a database record Share Pin Email Print rjp85 / Getty Images Software Databases Documents Spreadsheets Presentations Desktop Publishing Graphic Design Animation & Video by Mike Chapple An IT professional with more than 10 years of experience in the fields of databases and cybersecurity. Updated January 15, 2018 A superkey is either a single or a combination of attributes that can be used to uniquely identify a database record. A table might have many combinations that create superkeys. Superkey Example A table with the fields <Name>, <Age>, <SSN> and <Phone Extension>, for example, has many possible superkeys. Three superkeys are <SSN>, <Phone Extension, Name> and <SSN, Name>. Name Age SSN Phone Ext. Robert Jones 43 123-45-6789 123 Beth Smith 43 234-56-7890 456 Robert Jones 18 345-67-8901 789 As you can see, the columns of <Name> and <Age> have multiple entries with identical information. While the <Phone Extension> column can be used to locate an individual, a phone extension can be changed. Types of Superkeys Of those listed in the table above, only <SSN> is a candidate key, which is a special subset of superkeys that use a minimal amount of attributes to uniquely identify a record. The other columns contain information not necessary to identify records. The <SSN> can also be referred to as the minimal key or minimal superkey because it contains the least amount of information needed to identify an individual record. Along the same lines, a primary key can also be a superkey and a minimal key because it should uniquely pinpoint a record, and should rarely if ever, change. If the table didn't contain a <SSN> column then an employer could create employee numbers in order to be able to identify individuals. The new employee numbers would be called a surrogate primary key. This surrogate primary key would also serve as a superkey. Continue Reading Definition of a Determinant in a Database How to Choose a Primary Key for Your Database How BCNF Is Used in Relational Database Theory Primary Keys in a Database and What Makes a Good Key Protect Your Data by Normalizing It to at Least 2NF Database Terms You Need to Know What Is a Candidate Key? A Database Relation Might Not Be What You Think An Intro to Databases That's Suitable for the Brand New Beginner How Do You Put a Database in First Normal Form? A Beginner's Guide To Router Tables Ditch Your Spreadsheet for a Database to Access the Power of your Data Relationships Are the Basis for Relational Databases What Are Some Keys Take Make DB Management Easier? A Quick Guide to Understanding Database Dependencies What Is the Public Folder in Windows?