Suprakey

Suprakey

Supra, part of UTC Climate, Controls & Security, is a leading manufacturer of key-control and entry-management products. Supra has a 55-year history of producing convenient and secure entry solutions that permit authorized individuals to open locks, and our products eliminate the cost and inconvenience of issuing and tracking physical keys. Supra’s systems use electronic keys that enable our customers to monitor entry to their sites and use that information to increase productivity.  Informally, a superkey is a set of attributes within a table whose values can be used to uniquely identify a tuple. A candidate key is a minimal set of attributes necessary to identify a tuple, this is also called a minimal superkey. For example, given an employee schema, consisting of the attributes employeeID, name, job, and departmentID, we could use the employeeID in combination with any or all other attributes of this table to uniquely identify a tuple in the table. Examples of superkeys in this schema would be {employeeID, Name}, {employeeID, Name, job}, and {employeeID, Name, job, departmentID} which is the trivial superkey. In a real database we do not need values for all of those attributes to identify a tuple. We only need, per our example, the set {employeeID}. This is a minimal superkey – that is, a minimal set of attributes that can be used to identify a single tuple. So, employeeID is a candidate key.

Suprakey

Suprakey

Suprakey

Suprakey

Suprakey

Suprakey

Suprakey

Suprakey

Suprakey