1. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-1 David M. Kroenke’s Chapter Five: Data Modeling with the Entity-Relationship Model Part Three Database Processing: Fundamentals, Design, and Implementation

2. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-2 Mixed Patterns: The Line-Item Pattern

3. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-3 Mixed Patterns: The Line-Item Pattern

4. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-4 Look for a mixed pattern where: Strong entity has –multivalued composite group –ID-dependent Composite group element is –An identifier of another strong entity –Not ID-dependent

5. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-5 Mixed Patterns: Other Mixed Patterns

6. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-6 Mixed Patterns: Other Mixed Patterns

7. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-7 ID-Dependent Relationships: The Association Pattern

8. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-8 Mixed Patterns: The For-Use-By Pattern

9. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-9 Mixed Patterns: The For-Use-By Pattern

10. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-10 Recursive Relationships When an entity has a relationship to itself

11. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-11 Recursive Patterns: 1:1 Recursive Relationship

12. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-12 Recursive Patterns: 1:N Recursive Relationship

13. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-13 Recursive Patterns: N:M Recursive Relationship

14. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-14 The Data Modeling Process: Steps Plan project Determine requirements Specify entities Specify relationships Determine identifiers Specify attributes Specify domains Validate model

15. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-15 Sources for Data Modeling Requirements User interviews and user activity observations Existing forms and reports New forms and reports

16. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-16 Sources for Data Modeling Requirements (cont.) Existing manual files Existing computer files/databases Formally defined interfaces (XML) Domain expertise

17. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-17 Specifying Entities An entity is something that the users want to track; something the users want to keep data about

18. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-18 Specifying Relationships Includes: –Identity of the parent and child entities –Relationship type –Minimum and maximum cardinalities –Name of the relationships

19. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-19 Determining Identifiers Data Modeling Context E-R diagrams Identifier –attribute or group of attributes that –Uniquely identifies an entity instance

20. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-20 Specifying Attributes and Domains Find attributes on forms, reports, existing files, etc. add them to entities

21. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-21 Validating Model: When is a data model wrong? Does it accurately reflect –how users think –about their world?

22. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 5-22 David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10 th Edition) End of Presentation: Chapter Five Part Three