Data Integrity

Data Integrity means data validation or data checking process or Type Checking process.

Before storing user supplied information into the table server performs data integrity process in order to verify whether user supplying valid information or not.

If user supplies valid information then only it will stored into the table otherwise server raises an error message like 'Data Type Mismatch'.

We can achieve this Data Integrity in Three ways.

1. Data Types

2. Constraints

3. Triggers

Constraints: is nothing but condition on column.If we perform any operation against to constraint server raises an error message.

OR

It is mechanism automatically activated when user performs DML operations on the table.

We can place constraints (with constraint names or with out constraint names) on columns while creating the table or after creating the table but before inserting the values.

Data Integrity