Understand the definition of a super key and how it relates to candidate keys.
A Super Key is a set of one or more attributes (columns) that, when taken together, can uniquely identify a record (row) in a database table. The concept of a super key is broader than that of a primary or candidate key. The key requirement for a super key is simply uniqueness. Any set of attributes that guarantees you can pinpoint exactly one row is a super key. A candidate key is a special type of super key; it is a 'minimal' super key. This means that if you remove any attribute from a candidate key, it is no longer a super key. However, a super key does not have this minimality requirement. For example, let's consider our 'Employees' table with columns 'employee_id', 'ssn', and 'name'. The set {'employee_id'} is a super key because it uniquely identifies an employee. It is also a candidate key because it's minimal (you can't remove any attributes). The set {'ssn'} is also a super key and a candidate key. Now consider the set {'employee_id', 'name'}. This set is also a super key because 'employee_id' by itself is already unique, so adding 'name' to the set doesn't change the uniqueness. However, this set is NOT a candidate key because it is not minimal; you can remove the 'name' attribute, and the remaining attribute, 'employee_id', is still a unique identifier. In essence, every candidate key is a super key, but not every super key is a candidate key.