Database systems have been extremely important part in daily life, because it is processing daily huge amounts of data, it has been depended for wide field's such as bank system, personal system, medical system, communication system, …etc. Sensitive data is stored in database, in other words, data that an attacker looking for, is stored in database, so concerning of protecting these data have been a critical issue, this concern is the central theme of database security. Database security is ensures the secrecy, integrity, and availability of stored data. There are many techniques and mechanisms of security, which differs from multi sides, reliability, requirement, cost, speed, policy …etc, which means, a technique may be the best for some place, whereas the same technique is totally insufficient for other place. Multilevel of security is the good solution, systems that protected by multilevel of security are more secure than others, because, if one or some of techniques or mechanisms breakdown, there are other techniques that remain the system in secure.