Hi,

Dirty read is caused when the TRANSACTION ISOLATION LEVEL is set to READ UNCOMMITTED. This isolation level neither issues a shared lock nor issues exclusive locks. The statements in the current transaction can modify the data that has not been committed by other transactions. It leads to the removal or change in the data before the completion of the current transaction. The shared and exclusive locks prevent the statements in the current transaction to read the data that has not been committed by other transactions.