Final answer:
A superkey is a set of attributes in a database table that uniquely identifies each record in that table and may contain extra attributes that aren't necessary for uniqueness. It is crucial in database normalization for identifying candidate keys and defining primary keys.
Step-by-step explanation:
A superkey is a concept in database management systems. Specifically, it refers to a set of one or more columns (attributes) in a database table that can be used to uniquely identify each row in that table. The most important characteristic of a superkey is that it must contain a unique value for every tuple (row of data) within the table. However, a superkey may contain additional attributes that are not necessary for uniqueness.
An example of a superkey could be a combination of 'Employee ID' and 'Employee Name' in an employee table. While the 'Employee ID' alone might be enough to uniquely identify each employee (making it a candidate key), adding 'Employee Name' does not change the fact that the combination can uniquely identify each row, thus it still qualifies as a superkey.
The concept of superkey is important in the process of database normalization, which is the organization of data to reduce redundancy and improve data integrity. During normalization, superkeys can lead to the identification of candidate keys (minimal superkeys), which are then used to define the primary key of the table.