1. Slide 1 Chapter 05 – Part 1 Data Modeling with the Entity-Relationship Model

2. Slide 2 Content A. Computer Company Problem B. Solution

3. Slide 3 A. Computer Company Problem  ProgLtd is a company that places computer programmers at temporary jobs. They keep track on each programmer: the programmer's identification number, the programmer's last name, the programmer's first name, the programmer's rank (Junior, Senior...), gender, his/her hourly rate and what languages the programmer knows.  Beside, each programmer has been issued a badge which is used for enter their office. On each badge has following information: badge’s code, the programmer's identification number, issued date.

4. Slide 4  ProgLtd deals with clients who may require programmers who know a particular programming language. Once a programmer is assigned a temporary job, ProgLtd would like to keep track of when he/she started the job, the total number of hours he/she is expected to spend at job and the date he/she finished the job. That is in addition to the client name and phone number where the temp has been assigned.  Let’s design DB diagram for above requirements

5. Slide 5 B. Solution 1.Logical Analysis 2.Physical Analysis

6. Slide 6 1. Logical Analysis 1.1. Identify Entity 1.2. Identify Attribute 1.3. Identify Primary Identifier 1.4. Identify Alternative Identifier 1.5. Identify Mandatory Attribute 1.6. Identify Relationship

7. Slide 7 1.1. Identify Entity

8. Slide 8 1.2. Identify Attribute

9. Slide 9 1.3. Identify Primary Identifier

10. Slide 10 1.4. Identify Alternative Identifier

11. Slide 11 1.5. Identify Mandatory Attribute

12. Slide 12 1.6. Identify Relationship 1.6.1. Identify Maximum Cardinality 1.6.2. Identify Minimum Cardinality

13. Slide 13 1.6.1. Identify Maximum Cardinality 1.6.1.1. Maximum Cardinality Definition 1.6.1.2. Maximum Cardinality on Diagram

14. Slide 14 1.6.1.1. Maximum Cardinality Definition  Maximum Cardinality is the maximum number of entity instances that can participate in a relationship.  There are three types of maximum cardinality: One-to-One [1:1] One-to-Many [1:N] Many-to-Many [N:M]

15. Slide 15 1.6.1.2. Maximum Cardinality on Diagram

16. Slide 16 1.6.2. Identify Minimum Cardinality 1.6.2.1. Minimum Identifier Definition 1.6.2.2. Minimum Cardinality on Diagram

17. Slide 17 1.6.2.1. Minimum Identifier Definition  Minimum Cardinality is the minimum number of entity instances that must participate in a relationship.  Minimums are generally stated as either zero or one: IF zero [0] THEN participation in the relationship by the entity is optional, and no entity instance must participate in the relationship. IF one [1] THEN participation in the relationship by the entity is mandatory, and at least one entity instance must participate in the relationship.

18. Slide 18 1.6.2.2. Minimum Cardinality on Diagram

19. Slide 19 2. Physical Diagram

20. Slide 20 References  Database Processing – Chapter 5 Data Modelling with the Entity-Relationship Model David M. Kroenke

21. Slide 21