Module 6: Data Protection

Overview What does Data Protection include? Protecting data from unauthorized users and authorized users who are trying to update the same data simultaneously Using locking modes to achieve concurrency and consistency Implementing database security features to protect the database, database objects and data Using auditing features to monitor database activity

Concurrency and Consistency Isolation Levels and Concurrency Issues Concurrency and consistency are mutually opposing goals Oracle supports Read Committed and Serializable isolation levels  Achieves other levels through Row Versioning SQL Server Removes “Writers Blocking Readers – Readers Blocking Writers” with Snapshot Isolation SQL Server Supports all Four Isolation levels

Locking Locking granularity SQL Server supports lock escalation Explicit locking can be achieved by using lock hints in Both DBMS Oracle Locking SQL Server Locking Table Level Row level (default) Table Partition Page Row (default)

Demonstration 1: Isolation Level Behaviors In this demonstration you will see how to: Create a dirty read Create a committed read with blocking Create a snapshot isolation to remove blocking

Database Security Security is implemented in both DBMSs using logins and privileges Users can be classified as: Schema owners (SQL Server database object owners) Application users Administrative users User authentication can be achieved through the operating system login or database login SQL Server security depends on Windows security for features such as password expiration

Privileges and Roles Oracle and SQL Server both contain: System-level privileges – to perform actions against any object in the database Object-level privileges – to perform actions against specific schema objects Roles Group  System-level and object-level privileges SQL Server groups fixed roles: Server and Database Application roles in SQL Server  Implemented using application logic  Password protected

Demonstration 2: Provide Instance Security In this demonstration you will see how to: Create a Windows user account Associate a SQL Server login with the Windows user account

Auditing Auditing facilitates database activity monitoring Monitoring  statements, privileges, or objects Oracle audit key DDL and DML statements. SQL Server 2008 all actions (DDL and DML) are auditable. SQL Server audits can be enabled and generated, and then viewed from the audit target SQL Server Profiler offers various events that can be used for auditing SQL Server features such as DDL triggers and event notifications can aid in auditing

Review We defined concurrency and consistency and saw the challenges they offer We learned how concurrency and consistency can be balanced by use of isolation levels implemented using lock modes We learned about login and authentication at the database system level and database level, the various system and object level privileges and privilege management using roles We learned the basics of auditing functionality in SQL Server as compared to Oracle