A dirty read occurs when one user is updating or inserting a record while a different user is reading it, but the work is not yet committed to the database, as shown in the following example.
User A executes: INSERT INTO State (state, state_name, region)
VALUES (‘ME', 'Maine', ‘Northeast');
User B executes: SELECT * FROM State;
User B sees: state ‘ME'
User A executes: ROLLBACK WORK; User B has seen data that really did not exist.
