© 2002 by Prentice Hall 1 David M. Kroenke Database Processing Eighth Edition Chapter 18 Object- Oriented Database Processing

© 2002 by Prentice Hall 2 Object Oriented DBMS (OODBMS) Object Oriented DBMS (OODBMS) provide the ability to persistently store objects created in Object Oriented programming languages like Java, C#, and C++

© 2002 by Prentice Hall 3 Why not use a Traditional Relational DBMS? The traditional Relational DBMS stores data in tables, rows, and columns Objects have several complex structures that cannot be represented in tables, rows, or columns. –These structures include executable statements (i.e., methods) and pointers

© 2002 by Prentice Hall 4 OODBMS has Not Caught-On Recognizing that OODBMS is relatively new, very complicated, and very expensive, the technology has not been overly successful.

© 2002 by Prentice Hall 5 How are the Relational Database (RDBMS) Manufacturers Responding? The manufacturers of RDBMS are incorporating additional features to allow for the storage of more complex items. Oracle has been particularly active in incorporating these features. –The term object-relational DBMS has been coined to describe this classification of DBMS.

© 2002 by Prentice Hall 6 Object Oriented Programming (OOP) Object Oriented Programming (OOP) involves a new way of thinking about programming structures. In OOP, the data and instructions are combined into objects. In traditional programming, the data and instructions are disjointed.

© 2002 by Prentice Hall 7 OOP Terminology Encapsulated –complete unto itself Encapsulated Structure –an OOP object that has both attributes (properties) and methods Interface –external appearance of an object

© 2002 by Prentice Hall 8 OOP Terminology Implementation –the encapsulated internals of an object Inheritance –automatically assuming the attributes and methods of another object at a higher class Polymorphism –situation in which one name can be used to invoke different functions

© 2002 by Prentice Hall 9 OOP Terminology Object Class –the logical structure of an object (name, attributes, methods) Object Class Library –a group of object classes Object –an instance of an object class Transient vs. Persistent –volatile (i.e., temporal) vs. permanent

© 2002 by Prentice Hall 10 OOP Example

© 2002 by Prentice Hall 11 Object Persistence To make an object persistent, the data and structure embedded in the object must be stored.

© 2002 by Prentice Hall 12 Object Persistence Example

© 2002 by Prentice Hall 13 Swizzling Swizzling is the process of transforming permanent identifiers into in-memory addresses

© 2002 by Prentice Hall 14 Tasks for Object Persistence

© 2002 by Prentice Hall 15 Application Development Tasks for Object Persistence using Various Architectures

© 2002 by Prentice Hall 16 Object Persistence using Oracle Oracle saves objects in one of four types: –Column Objects –Variable Length Arrays –Nested Tables –Row Objects

© 2002 by Prentice Hall 17 Oracle’s Column Object Create Type obj_name as Object ( anameVarchar2(15), aphone Char (10), asalary Number);

© 2002 by Prentice Hall 18 Oracle’s Variable Length Array Create Type apt_unit As Object ( aptnbrchar (5), nbrbedsint); Create Type aptlist1 As Varray(20) of apt_unit;

© 2002 by Prentice Hall 19 Oracle’s Nested Tables Create Type apt_unit As Object ( aptnbrchar (5), nbrbedsint); Create Type aptlist2 As Table of apt_unit;

© 2002 by Prentice Hall 20 Oracle’s Row Objects Create Type obj_apt As Object ( aptnamevarchar2 (15), aptnbrnumber); Create Table apartments Of obj_apt;

© 2002 by Prentice Hall 21 OODBMS Advantages and Disadvantages

© 2002 by Prentice Hall 22 ODBMS Standards SQL3 –an extension to SQL92 that includes support for OODBMS Abstract data type (ADT) –user-defined structure that is equivalent to an OOP object

© 2002 by Prentice Hall 23 Object Data Management Group’s ODMG-93 Report The Object Data Management Group (ODMG), a consortium of object database vendors and experts, developed a definition of interfaces for object data management products (ODMG-93).

© 2002 by Prentice Hall 24 Key Elements of the ODMG Object Model

© 2002 by Prentice Hall 25 ODMG Relationship Operations

© 2002 by Prentice Hall 26 David M. Kroenke Database Processing Eighth Edition Chapter 18 Object- Oriented Database Processing