Question

Difference between candidate key and primary key

Answer 1

it's very easy... candidate keys are those which we can use as primary key..but there is only one primary key in a table.

Answer 2

Primary Key: 1)Each relation has atleast one column for which each row must have a unique value . Such a attribute is called a primary key.
2) Only one primary key can be defined Foer each table.
Candidate Key: 1) Set of all the attributes which can identify each tuple in a relation uniquely are called candidate keys.
2) Out of them one can be choosen as primary key.