Fundamentals Of Database Engineering By Hussein Nasser Fix -

| Level | Phenomenon prevented | |--------|----------------------| | Read Uncommitted | – (dirty reads possible) | | Read Committed | Dirty reads | | Repeatable Read | Non-repeatable reads | | Serializable | Phantom reads + all above |

When two users try to update the same data simultaneously, chaos can ensue. Nasser covers the locking mechanisms that prevent this. fundamentals of database engineering by hussein nasser