Akamai Interview Question
Software Engineer / DevelopersCountry: India
super key: Entire row in a table is called a super key
candidate keys: All the attributes which can be choosen as a primary key is called candidate keys these keys can uniquely identify the row
primary key: its one among the candidate key which is choosen as a primary key used to identify a row uniquely
ip a primary key composed of more than one attribyte its called as a composite key
Candidate Key
- Madhav September 18, 2011A candidate key is a combination of attributes that can be uniquely used to identify a database record without any extraneous data. Each table may have one or more candidate keys. In general, one of these candidate keys is selected as the table primary key.
Superkey
A superkey is a combination of attributes that can be uniquely used to identify a database record. A table might have many superkeys. Candidate keys are a special subset of superkeys that do not have any extraneous information in them.
A primary key is therefore a minimum superkey.
Composite Key
A primary key that made up of more than one attribute is known as a composite key.