|Oracle 8i Data Cartridge Developer's Guide
Release 2 (8.1.6)
Part Number A76937-01
What Is a Data Cartridge?, 4 of 7
The Oracle8i server provides services for basic data storage, query processing, optimization, and indexing. Various applications use these services to access database capabilities. However, data cartridges have specialized needs because they incorporate domain-specific data. To accommodate these specialized applications, the basic services have been made extensible in the Oracle8i series of releases.
That is, where some aspects of a standard Oracle8i service are not adequate for the processing a data cartridge requires, you as the data cartridge developer can provide services that are specially tuned to your cartridge. Every data cartridge can provide its own implementations of these services. These specialized implementations are registered with the server using the Oracle8i extensibility interfaces.
For example, suppose you want to build a spatial data cartridge for geographical information systems (GIS) applications. In this case, you may need to implement routines that create a spatial index, insert an entry into the index, update the index, delete from the index, and perform any other required operations. To do this you would register your implementations with the Oracle8i server using extensible indexing interface, and then the server will invoke your implementation every time indexing operations were needed for spatial data. In effect, you extend the indexing service of the server.