Course Details

Unit 1: Introduction ————————————– LH 4

  • A major Change: The relational Data Model
  • Object Roles in Databases
  • Sample uses of Object-oriented Databases
  • Benefits of Object Orientation

Pre-requisite for OODBMS

  • Any Type of Database (Data Model, Relational Model, E-R Data Model)
  • Object-Oriented Programming (C++, Java, etc.)

A Major Change: The relational Data Model

  • The relational model (RM) for database management is an approach to managing data using a structure and language consistent with first-order predicate logic
  • database organized in terms of the relational model is a relational database.

Why do we need OODBMs?

  • Limitation of Relational Data Model.
  • Requirement of Advance DB Applications.
  • New Applications:
    • CAD/CAM Design
    • Real Time control System
    • Multimedia interface

Data Modeling

Data Modeling is the art of identifying the entities that must be represented in a database and the relationships among those entities.

Hierarchical Data Model

  • Data organized in a tree a parent can have many children
  • a child can have only one parent
  • Records described by entity types
  • 1:N (one-to-many) relationships
  • Query by path navigation
  • Examples
    • File system
    • LDAP (Lightweight Directory Access Protocol )
    • Windows Registry and Active Directory
    • XML documents and XQuery

  • Implemented by IBM’s Information Management System (IMS)
  • Allows only one-to-one or one-to-many relationships between entities.
  • The benefit of a hierarchical database is that its navigational nature makes access very fast when you are following the predefined relationships.
  • The inability to give an entity multiple parents and the absence of direct data make it unsuitable for environments where ad hoc queries are important.

Network Data Models

  • Data organized in graph (lattice)
    • A parent can have many children
    • A child can have many parents
  • Record types define properties
  • Set type defined relationships
    • Parent-child
  • Query by graph navigation

Relational Model

  • Data organized as tuples in relations
  • The link between data tuples
    • Primary and foreign keys
  • Relation algebra
    • The project, select, join
  • Relational normal forms
  • Declarative language
  • Examples
    • Oracle, MS SQL Server, IBM DB2,PostgreSQL , MySQL

Object-Oriented Data  Model

  • Development of an object-oriented paradigm brought about a fundamental change in the way we look at data and the procedures that operate on data.
  • Traditionally, data and procedures have been stored separately, the data and their relationships in a database, the procedures in an application program.
  • Object orientation, however, combines an entity’s procedures with its data.
  • Entities become self-contained units that can be reused and moved around with relative ease.

Limitation of Relation Data Model

  • Data dependency on the data model
  • The power of the Relational Database is also a drawback of RDBMS.
  • Integrity Constraints.

Why Object-Oriented Database Management System?

  • To overcome the limitation of RDBMS.
  • Store the multimedia data.
  • To facilitate the advanced programming logic and business logic.
  • To Store data of new application like CAM/CAD, multimedia data.
  • To overcome performance issues arise due to RDBMs Models.

Introduction of OODMS

  • OODBMS is a database management system (DBMS) that supports the modeling and creation of data as objects.
  • An object-oriented database system must satisfy two criteria: it should be a DBMS, and it should be an object-oriented system
  • Objects basically consist of the following:
    • Attributes – Attributes are data which defines the characteristics of an object. This data may be simple such as integers, strings, and real numbers or it may be a reference to a complex object.
    • Methods – Methods define the behavior of an object and are what was formally called procedures or functions.

Uses of Object Oriented Database

  • CAS Applications (CASE-Computer Aided Software Engineering, CAD-Computer Aided Design, CAM-Computer Aided Manufacture)
  • Multimedia Applications
  • Projects that change over time.
  • Commerce

Benefits of Object Orientation

  • Object-oriented databases make the promise of reduced maintenance, code reusability, real world modeling, and improved reliability and flexibility.  Below are some benefits of Object Oriented Approach.
  • Reduced Maintenance
  • Real-World Modeling
  • Improved Reliability and Flexibility
  • High Code Reusability
  • Better concurrency control

Object Roles in Databases

  • Pure object-oriented DBMSs
    • Is based solely on the object-oriented data model.
    • Used in mission critical systems
  • Hybrid or post-relational DBMSs
    • Is primarily based on relational but stores objects in relations

Sample Uses for Object-Oriented Databases

  • OODB is being used today in a wide range of organizations for a wide range of purposes
    • CAD/CAM Computer-Aided Design and Computer-Aided Manufacture Applications
    • ECAD And MCAD
      • Involves in research, design, and development of engineering systems structures
    • RealTime  Control System
    • Multimedia Interface

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