Chapter2 Database Fundamentals Slides Powerpoint

Fundamentals of Database

1. Chapter 2: Database Modeling Concepts Based on 'Asasat Database' (TVETA Afghanistan) Prepared by Ahmad Fawad Azizi

2. Learning Objectives - Explain the purpose of database models - Identify types of database models - Differentiate between hierarchical, network, relational, and object models

3. What is Database Modeling? Database modeling defines the structure and relationships of data in a database system. It shows how data elements are connected and how they can be accessed and managed.

4. Major Types of Database Models 1. Hierarchical Model 2. Network Model 3. Relational Model 4. Object-Relational Model 5. Object-Oriented Database Model

5. Hierarchical Database Model - Oldest model (used in 1960s–1970s) - Data is organized in a tree structure (Parent–Child) - Each child has only one parent - Example: Organizational structure, file directory systems

6. Advantages of Hierarchical Model - Fast data retrieval - Simple structure - Good for 1-to-many relationships

7. Disadvantages of Hierarchical Model - Complex to modify or search - No many-to-many relationships - Redundant data - Rigid structure

8. Network Database Model - Extension of hierarchical model - Allows many-to-many relationships - Data is represented as records connected by links (pointers) - Developed by CODASYL in late 1960s

9. Advantages of Network Model - Supports complex relationships - Faster data access - Less redundancy compared to hierarchical model

10. Disadvantages of Network Model - Complex structure - Hard to modify or design - Requires skilled programmers

11. Relational Database Model - Proposed by E.F. Codd in 1970 - Data stored in tables (rows and columns) - Uses primary and foreign keys to relate data - SQL used for data manipulation

12. Codd’s 12 Rules (Summary) 1. Information Rule 2. Guaranteed Access 3. Systematic Treatment of Nulls 4. Active Online Catalog 5. Comprehensive Data Sub-language 6. View Updating 7. High-Level Insert, Update, Delete 8. Physical & Logical Data Independence 9. Integrity Independence 10. Distribution Independence 11. Non-Subversion Rule

13. Advantages of Relational Model - Simplicity and flexibility - Powerful querying via SQL - Data independence - Data integrity and consistency - Suitable for business and scientific applications

14. Disadvantages of Relational Model - Slower for large complex data - Expensive implementation - Difficult for multimedia or hierarchical data

15. Object-Relational Model - Combines relational and object-oriented principles - Supports objects, classes, and inheritance - Stores data as objects with attributes and methods - Used in modern systems like PostgreSQL and Oracle

16. Object-Oriented Database Model - Based on object-oriented programming concepts - Data and behavior stored together in objects - Supports inheritance, encapsulation, and polymorphism - Used in applications like CAD, AI, multimedia

17. Comparison of Models Hierarchical: Tree structure, 1-to-many only Network: Graph structure, many-to-many Relational: Tables, keys, and SQL Object-Oriented: Objects and classes Object-Relational: Mix of relational and object features

18. Summary • Database models define how data is structured and related. • Relational model remains the most widely used. • Object-oriented and object-relational models are used in advanced applications. • Understanding models helps in efficient database design.