1. 1 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Chapter 5 Database Design 1: Normalization

2. 2 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Objectives u Discuss functional dependence u Define first normal form, second normal form, and third normal form u Describe the problems associated with tables (relations) that are not in first normal form, second normal form, or third normal form along with the mechanism for converting to all three

3. 3 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Objectives u Discuss the problems associated with incorrect conversions to third normal form u Define fourth normal form u Describe the problems associated with tables (relations) that are not in fourth normal form and describe the mechanism for converting to fourth normal form

4. 4 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Functional Dependence u Column B is functionally dependent on Column A if A’s value determines a single value for B at a given time u Given A, a single value for B can be determined

5. 5 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Functional Dependence Example Figures 5.3 - 5.4 Rep Table Where LastName can determine record Rep Table Where LastName cannot determine record

6. 6 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Keys u Column(s) C is primary key for table T if: Property 1: All columns in T are functionally dependent on C Property 2: No subcollection of columns in C (assuming C is a collection of columns and not just a single column) also has Property 1 u Candidate Keys l Column(s) on which all other columns in table are functionally dependent u Alternate Keys l Candidate keys not chosen as primary keys

7. 7 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski First Normal Form (1NF) u Unnormalized table l Contains a repeating group u Table in 1NF l Contains no repeating groups u Removal of repeating groups is starting point in quest for problem-free tables

8. 8 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 1NF Example Figure 5.5 Unnormalized Table

9. 9 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 1NF Example (con’t.) Figure 5.6 Conversion to 1NF

10. 10 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Second Normal Form (2NF) u 1NF Tables may contain problems l Redundancy l Update Anomalies u Update, inconsistent data, additions, deletions u Occur because a column is dependent on a portion of a multi-column primary key u 2NF Table l In 1NF and no nonkey column is dependent on only a portion of the primary key

11. 11 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Dependency Diagram for Orders Figure 5.8

12. 12 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 2NF Example Figure 5.9a

13. 13 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 2NF Example Figure 5.9b

14. 14 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Third Normal Form (3NF) u 2NF Tables may still contain problems l Redundancy and wasted space l Update Anomalies u Update, inconsistent data, additions, deletions u Occur because a column is dependent on a portion of a multi-column primary key u 3NF Table l In 2NF and the only determinants contained are candidate keys

15. 15 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Customers Dependency Diagram Figure 5.11

16. 16 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 3NF Example Figure 5.12a

17. 17 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 3NF Example Figure 5.12b

18. 18 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Incorrect Decomposition Example Figure 5.13a

19. 19 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Incorrect Decomposition Example Figure 5.13b

20. 20 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 2nd Incorrect Decomposition Figure 5.14a

21. 21 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 2nd Incorrect Decomposition Figure 5.14b

22. 22 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Fourth Normal Form (4NF) u 3NF Tables may still contain problems l Dependencies l Update Anomalies u Update, additions, deletions u Occur because of multivalued dependencies u 4NF Table l In 3NF and has no multivalued dependencies

23. 23 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Incorrect 4NF Example Figure 5.15

24. 24 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 4NF Example Figure 5.16a

25. 25 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski 4NF Example Figure 5.16b

26. 26 5 Concepts of Database Management, 4 th Edition, Pratt & Adamski Normal Forms Figure 5.17