Abstract Data Typing Oracle Tips by Burleson Consulting

High Performance Data Warehousing

Database Architectures For The 1990s

The Object Layer 

Rather than rebuild the Oracle engine as an object-oriented architecture, Oracle has decided to keep the base relational engine and add object functionality on top of the standard relational architecture. While claiming to be an active member in the Object Management Group (OMG), Oracle has departed from the OMG's standard for "pure" object databases as defined by the Object Data Management Group (ODMG). Oracle's intent is to provide a generic relational database while extending the architecture to allow for objects. The object layer of Oracle8 claims to have the following features: abstract data typing, abstraction, inheritance, polymorphism, encapsulation, extensibility, and the IS-A construct.

Abstract Data Typing (ADTs)

Rather than being constrained to the basic relational datatypes of int, varchar, and float, Oracle8 allows the definition of datatypes that may be composed of many subtypes. For example, the following data definition could be implemented in Oracle8 as an address datatype:

03 ADDRESS.
05 street-address varchar(30).
05 city-address varchar(30).
05 zip-code number(5).

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This is an excerpt from "High Performance Data Warehousing", copyright 1997.

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