Entity Integrity and Referential Integrity

Entity integrity and Referential integrity are the basis for ensuring data integrity.

Entity integrity ensures that there are no duplicate records and the primary key attributes are not NULL. The primary key helps out in uniquely identifying the row in a table and the value of the primary key should be specified and should not be NULL.

Referential integrity ensures that if a relational table has a foreign key, then every value of the foreign key in a table must be the same as that of related table’s primary key or the foreign key should be NULL.