Chapter 25.  Object-Oriented Aspects of PL/SQL

Chapter 25. Object-Oriented Aspects of PL/SQL PL/SQL has always been a language that supports traditional procedural programming styles such as structured design and functional decomposition. Using PL/SQL packages, it is also possible to take an object-based approach, applying principles such as abstraction and encapsulation to the business of manipulating relational tables. Later versions of Oracle have introduced direct support for object-oriented programming (OOP), providing a rich and complex type system, complete with support for type hierarchies and "substitutability." In the interest of summarizing this book-sized topic into a modest number of pages, this chapter presents a few choice code samples to demonstrate the most significant aspects of object programming with PL/SQL. These cover the following areas: Creating and using object types Inheritance and substitutability Type evolution Pointer (REF)-based retrieval Object views Among the things you will not find in this chapter are: Comprehensive syntax diagrams for SQL statements dealing with object types Database administration topics such as importing and exporting object data Low-level considerations such as physical data storage on disk I'd like to introduce the topic with a brief history.