Super Key
Set of attributes that can uniquely identify records within a table
Super key can have redundant attributes as well
Candidate Key
Set of non-redundant attributes than can be used to identify records in a table
Primary Key
The key from the set of candidate keys that is selected to be used as the key for the table
Alternate Key
Keys from the set of candidate keys that can be used as primary key but isn’t the current primary key
Foreign Key
Columns of an table that act as reference to primary key of another key
Used to show relation between tables
Composite Key
A key that consist of more than one column to uniquely identify an column in an table
DBMS Keys: Candidate, Super, Primary, Foreign Key Types with Example