1. Security

2. Security
Security of data is important concept in DBMS because it is essential to safeguard the data against any unwanted users.
It is protection from malicious attempts to steal or modify data.

3. There are five different level of security
Database system level
Operating
Network level
Physical level
Human level

4. 1. Database system level
Authentication and authorization mechanism to allow specific users access only to required data.

5. 2. Operating Protection from invalid logins
File level access protection
Protection from improper use of “superuser” authority.
Protection from improper use of privileged machine instructions.

6. 3. Network level
Each site must ensure that it communicates with trusted sites.
Links must be protected from theft or modification of messages.
Mechanisms used
Identification protocol (password based)
Cryptography

7. 4. Physical level
Protection of equipment from floods, power failure etc.
Protection of disks from theft, erasure, physical damage etc.
Protection of network and terminal cables from wire tapes, non invasive electronic eavesdropping, physical damage etc.,
Solution
Replication hardware- mirrored disks, dual busses etc.
Multiple access paths between every pair of devices.
Physical security by locks, police etc.
Software techniques to detect physical security breaches.

8. 5. Human level Protection from stolen passwords, sabotage, etc.
Solution
Frequent change of passwords.
Use of “non-guessable” passwords.
Log all invalid access attempts.
Data audits
Careful hiring practices.