Briefly explain database security.

Database security involves implementing measures to protect a database from unauthorized access, data corruption, and other threats. Its requirements include ensuring confidentiality, integrity, availability, and accountability of the data within the database.

1. Confidentiality: Data should only be accessible to authorized users and entities.
2. Integrity: Data should remain accurate and consistent throughout its lifecycle, and unauthorized modifications or deletions should be prevented.
3. Availability: Users should be able to access the database and its resources as needed without interruption.
4. Accountability: Activities within the database should be traceable to specific users, ensuring accountability for any changes or access.

Part 2: Multilevel database security involves managing data with different sensitivity levels within the same database system. This includes sensitive and insensitive data, where sensitive data requires higher security measures.

1. Sensitive and Insensitive Levels: Data is classified into different sensitivity levels based on its importance and confidentiality. Sensitive data requires stricter security measures, while insensitive data may have fewer restrictions.
2. Integrity Lock: Implementing mechanisms such as integrity locks ensures that sensitive data cannot be modified or accessed without proper authorization.
3. Trusted Frontend: Utilizing a trusted frontend interface helps enforce security policies and access controls, ensuring that only authorized users can interact with sensitive data.
4. Communicator Filter: Implementing filters or gateways between different sensitivity levels ensures that data flows securely between them, preventing unauthorized access or leakage.
5. Distributed Database: In a distributed database environment, ensuring multilevel security involves implementing consistent security policies and controls across all nodes and segments of the database.
6. Restricted Views: Providing restricted views allows users to access only the data they are authorized to see, based on their security clearance and role within the organization.