Oracle provides a number of features such as data concurrency and consistency, manageability, backup and recovery, client-server architecture, business intelligence, database security, and data integrity. These features are discussed next.
Data Concurrency and Consistency
Data concurrency is the property which implies that the data can be accessed by multiple users at the same time. Data consistency is a property that ensures that each user can see a consistent view of data, which means the user can view the changes made by him in his own transactions as well as the transactions of other users.
Manageability
Oracle manages the database itself and it tunes the database automatically. Oracle has the following self-managing database features:
- Automatic undo management.
- Dynamic memory management.
- Oracle-managed files.
- Free space management.
- Multiple block sizes.
- Recovery management system.
Backup and Recovery
It is one of the most important features of Oracle. The backup of data is created to protect data in case the system crashes or the data gets corrupt. It consists of files such as datafiles, control files, redo logs files, and so on. There are different types of backups available in Oracle 11g.
Recovery means restoring a backup file into a specified location. In case of crash of database, Database Administrator recovers the data by using the recovery method.
Client-Server Architecture
The Oracle database allows multiprocessing, which is also known as distributed processing system. In this system, many users access data at the same time. This system reduces the load on the processor as the tasks are assigned to different processors. In the client-server architecture, the database system is divided into two parts: client machine and server machine.
Business Intelligence
Oracle provides various business intelligence features such as data warehousing, ELT (extraction, transformation, and loading), materialized views, table compression, parallel execution, bitmap indexes in data warehousing, analytic SQL, and so on.
Database Security
Oracle provides security features for controlling unauthorized access to database. These features include prevention of unauthorized data access, prevention of unauthorized access to schema objects, and storing all user actions. Oracle associates each database user with a schema by the user’s name. By default, each database user creates and has access to all objects in the corresponding schema.
Data Integrity
Data integrity allows you to specify certain rules for the quality of the data, which the data in a database needs to satisfy. If a user inserts data that doesn't meet the specified requirements, Oracle will not allow the user to insert the data. Therefore, it is important that the data adheres to the set of rules determined by the database administrator or the application developer. There are five data integrity constraints in Oracle that enable you to enforce the rules on the data. These constraints are Not Null, Unique Key, Primary Key, Foreign Key, and Check.
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