✓ What is Data Integrity
✓ Types of Constraints
✓ Primary key vs Unique Key

It is important that data adhere to a predefined set of rules, as determined by the database administrator or application developer. Oracle provides constraints to enforce data integrity in database.
You can go through our RDBMS Documentation for better understanding on data integrity in RDBMS.
This chapter explains how to use integrity constraints to enforce the business rules associated with your database and prevent the entry of invalid information into tables.