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