Oracle Essentials: Oracle9i, Oracle8i and Oracle8, Second Edition

Using the Extensibility Framework in Oracle

Oracle allows users to extend the basic functionality of the database. Oracle’s extensibility framework provides entry points in which developers can add their own features to the existing feature set. By using this framework you can do the following:

Add new relational or set operators for use in SQL statements

These new operators can be useful when working with extended datatypes, such as multimedia or spatial data. You can create relational operators that relate specifically to a particular datatype, such as the relational operator CLOSER TO, which you can use in SQL statements that access spatial data.

Create cooperative indexing

Cooperative indexing is a scheme in which an external application is responsible for building and using an index structure that you can use with complex datatypes. The indexes created are known as domain indexes.

Extend the optimizer

If you use extended indexes, user-defined datatypes, or other features, you can extend the statistics-collection process or define selectivity and cost functions for these extended features. The cost-based optimizer can then use these to choose an appropriate query plan.

Add cartridge services

These are services used by Oracle database extensions (such as the spatial capabilities) providing memory management, context management, parameter management, string and number manipulation, file I/O, internationalization, error reporting, and thread management. These services are available ...