|Oracle9i OLAP User's Guide
Release 2 (9.2)
Part Number A95295-01
Overview, 3 of 5
The Oracle9i Integrated Relational-Multidimensional Database
Oracle provides multidimensional technology within the database. Organizations no longer need to choose between a multidimensional OLAP database and a relational database. By integrating OLAP into the database, Oracle provides the power of a multidimensional database while retaining the manageability, scalability, and reliability of the Oracle database and the accessibility of SQL. The Oracle database provides the functionality of a specialized analytic database while eliminating the need for a separate database system.
The advantages of a single integrated relational-multidimensional database when compared to two separate relational and multidimensional databases are many:
- Simplified management. All management tasks are consolidated into a single database and can be managed through Oracle Enterprise Manager or PL/SQL.
- High availability. Oracle OLAP has the same scalability and high reliability as the Oracle database, including support for Real Application Clusters and Oracle Data Guard. Real Application Clusters allow multiple instances of the database to work cooperatively against a single disk image of the database. When more processing power is needed, another server can be added to the cluster. If a server fails, then another server automatically takes over. Oracle Data Guard protects against complete site failure, for instance, in the event of an unprotected power failure. In the event of site failure, Oracle Data Guard automatically switches to a backup instance at a different site.
- High security. Oracle provides complete security to all data in the database, including multidimensional data. All users are defined in a single user catalog and are assigned privileges using standard security features such as roles and privileges. More finely grained access privileges can also be granted.
- Open access. Both relational and multidimensional data can be accessed through SQL and the OLAP API. Application developers can choose to use the calculation and data navigation features of the OLAP API, or they can leverage their investment in SQL to access multidimensional data. Any OLAP calculation can be queried using SQL. Standard reporting applications can present the results of complex multidimensional calculations. Ad-hoc querying tools can provide new calculation functions.
- Reduced update time. Oracle allows data to be stored in either relational or multidimensional tables and provides access to both through SQL and the OLAP API. Thus, data does not need to be replicated in two data stores. The typical two-step data maintenance process (update the data warehouse, then update the multidimensional database) is now reduced to a single step. The result is a corresponding reduction in the interval between the time the data is available from the source system and the time the data is available to users for analyses.
- Improved data reliability. Because data does not need to be replicated between the relational tables and multidimensional tables, it cannot get out of synchronization. All users have access to the same version of the data as soon as changes are committed to the database.
The Oracle relational database and Oracle OLAP provide complementary functionality to support the most versatile and high performance applications. The database and SQL engine provide detail data, summary management, and one-dimensional calculations using the SQL-99 OLAP extensions. Oracle OLAP expands these capabilities to provide forecasting, modeling, what-if scenarios, and multidimensional calculations.