1 / 36

AssignmentPoint

Lecture on Object Oriented Databases Database Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel. www.AssignmentPoint.com. In this chapter, you will learn:. What basic concepts govern OO systems What effect OO concepts are likely to have on data modeling and design

peggie
Download Presentation

AssignmentPoint

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Lecture onObject Oriented DatabasesDatabase Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel www.AssignmentPoint.com www.assignmentpoint.com

  2. In this chapter, you will learn: • What basic concepts govern OO systems • What effect OO concepts are likely to have on data modeling and design • How OO features are related to the more traditional relational and E-R models • What the basic features of an OO database management system (OODBMS) are • About the advantages and disadvantages of OODBMSs www.assignmentpoint.com

  3. Object Orientation • Object Orientation • Set of design and development principles • Based on autonomous computer structures known as objects • OO Contribution areas • Programming Languages • Graphical User Interfaces • Databases • Design • Operating Systems www.assignmentpoint.com

  4. Evolution of OO Concepts • Concepts stem from object-oriented programming languages (OOPLs) • Ada, ALGOL, LISP, SIMULA • OOPLs goals • Easy-to-use development environment • Powerful modeling tools for development • Decrease in development time • Make reusable code • OO Attributes • Data set not passive • Data and procedures bound together • Objects can act on self www.assignmentpoint.com

  5. OO Concepts: Objects • Abstract representation of a real-world entity • Unique identity • Embedded properties • Ability to interact with other objects and self • OID • Unique to object • Not a primary key • Attributes • Called instance variables • Domain • Object state • Object values at any given time www.assignmentpoint.com

  6. OO Concepts: Objects (con’t.) • Methods • Code that performs operation on object’s data • Has name and body • Messages • Invokes method • Sent to object • Classes • Collection of similar objects • Shares attributes and structure • Protocol • Represents object’s public aspect www.assignmentpoint.com

  7. OO Concepts: Objects (con’t.) • Class hierarchy • Code that performs operation on object’s data • Has name and body www.assignmentpoint.com

  8. Object Characteristics Figure 11.7 www.assignmentpoint.com

  9. Class Hierarchy • Superclass • Subclass • Class lattice Figure 11.8 www.assignmentpoint.com

  10. Inheritance • Ability of object to inherit the data structure and behavior of classes above it • Single inheritance • Class has one immediate superclass Figure 11.9 www.assignmentpoint.com

  11. Inheritance (con’t.) • Multiple • Class has more than one immediate superclass Figure 11.10 www.assignmentpoint.com

  12. Method Overriding • Method redefined at subclass level Figure 11.12 www.assignmentpoint.com

  13. Polymorphism Allows different objects to respond to same message in different ways Figure 11.13 www.assignmentpoint.com

  14. Abstract Data Types (ADT) • Describes a set of similar objects • Differs from conventional data types • Operations are user-defined • Uses encapsulation • Definitions needed for creation • Name • Data representation • Abstract data type operations and constraints www.assignmentpoint.com

  15. Object Classification • Simple • Only single-valued attributes • No attributes refer to other object • Composite • At least one multivalued attribute • No attributes refer to other object • Compound • At least one attribute that references other object • Hybrid • Repeating group of attributes • At least one refers to other object www.assignmentpoint.com

  16. Characteristics of OODM • Supports complex objects • Must be extensible • Supports encapsulation • Exhibit inheritance • Supports object identity www.assignmentpoint.com

  17. OO vs. E-R Model Components Table 11.3 www.assignmentpoint.com

  18. Shared Representation for all Objects of the Class Person Figure 11.14 Figure 11.15 www.assignmentpoint.com

  19. Referential Sharing of Objects Figure 11.19 www.assignmentpoint.com

  20. Class-Subclass Relationship Figure 11.21 Figure 11.20 www.assignmentpoint.com

  21. Interobject Relationships • Attribute-Class Link • Object’s attribute references another object • Relationship Representation • Related classes enclosed in boxes • Double line on right side indicates mandatory • Connectivity indicated by labeling each box • 1:M • M:N • M:N with an Intersection Class www.assignmentpoint.com

  22. 1:1 and 1:M Relationships Figure 11.24 www.assignmentpoint.com

  23. Employee-Dependent Relationship Figure 11.25 www.assignmentpoint.com

  24. Representing the M:N Relationship Figure 11.26 www.assignmentpoint.com

  25. Representing the M:N Relationship with Associated Attributes Figure 11.27 www.assignmentpoint.com

  26. Representing the M:N Relationship with Intersection Class Figure 11.28 www.assignmentpoint.com

  27. Object Space Representation Figure 11.29 www.assignmentpoint.com

  28. Late and Early Binding • Late binding • Data type of attribute not known until runtime • Allows different instances of same class to contain different data types for same attribute • Early binding • Allows database to check data type at compilation or definition time www.assignmentpoint.com

  29. OODM vs. E-R Data Models • Object, Entity, and Tuple • OODM object has behavior, inheritance, and encapsulation • OO modeling more natural • Class, Entity Set, and Table • Class allows description of data and behavior • Class allows abstract data types • Encapsulation and Inheritance • Object inherits properties of superclasses • Encapsulation hides data representation and method www.assignmentpoint.com

  30. Object ID Not supported in relational models Relationships OODM Interclass references Class hierarchy inheritance Relational models Value-based approach Access Relational models SQL OODM Navigational Set-oriented access OODM vs. E-R Data Models (con’t.) www.assignmentpoint.com

  31. OODBMS • Database management system integrates benefits of typical database systems with OODM characteristics • Handles a mix of data types • Follows OO rules • Follows DBMS rules www.assignmentpoint.com

  32. OO and Database Design • Provides data identification and the procedures for data manipulation • Data and procedures self-contained entity • Iterative and incremental • DBA does more programming • Lack of standards www.assignmentpoint.com

  33. OODBMS Advantages • More semantic information • Support for complex objects • Extensibility of data types • May improve performance with efficient caching • Versioning • Reusability • Inheritance speeds development and application • Potential to integrate DBMSs into single environment www.assignmentpoint.com

  34. OODBMS Disadvantages • Strong opposition from the established RDBMSs • Lack of theoretical foundation • Throwback to old pointer systems • Lack of standard ad hoc query language • Lack of business data design and management tools • Steep learning curve • Low market presence • Lack of compatibility between different OODBMSs www.assignmentpoint.com

  35. OO Influences on Relational Model • Extensibility of new user-defined (abstract) data types • Complex objects • Inheritance • Procedure calls (rules or triggers) • System-generated identifiers (OID surrogates) www.assignmentpoint.com

  36. The Next Generation of DBMS • Object-oriented database systems • Artificial intelligence systems • Expert systems • Distributed database • The Internet www.assignmentpoint.com

More Related