1. Normalization Data Design - Mr. Ahmad Al-Ghoul
In this sequence we will study a normalization example

2. learning Objectives
Explain the concept of normalization

3. A Normalization Example
The three steps of data normalization are
Remove all repeating groups and identify the primary key
Ensure that all nonkey attributes are fully dependent on the primary key
Remove any transitive dependencies, attributes which are dependent on other nonkey attributes

4. A Normalization Example
To show the normalization process, consider the familiar situation which might depict several entities in a school advising system: ADVISOR, COURSE, and STUDENT
The relationships among the three entities are shown in the ERD below
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5. A Normalization Example
In this example we will discuss the normalization rules for these three entities, to show how you can design a validate ERD
Note that the relationship between student and course is many to many relationship (M:N) which can not create physically and as we said previously we must solve this problem by dividing this relationship to two one to many (1:M) relationship by adding a new entity called Associative entity
the STUDENT table contains fields that relate to the ADVISOR and COURSE entities, so you can decide to begin with the initial design for the STUDENT table.

6. A Normalization Example
Unnormalized student table
STUDENT (STUDENT-NUMBER, STUDENT-NAME, TOTAL-CREDITS, GPA, ADVISOR-NUMBER, ADVISOR-NAME, (COURSE-NUMBER, COURSE-DESC, NUM-CREDITS, GRADE))
Repeating groups
The STUDENT table is unnormalized because it contains a repeating group that represents the courses each student has taken.
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7. A Normalization Example
1NF
To convert the STUDENT record to 1NF, you must expand the primary key to include the key of the repeating group
STUDENT (STUDENT-NUMBER, STUDENT-NAME, TOTAL-CREDITS, GPA, ADVISOR-NUMBER, ADVISOR-NAME, COURSE-NUMBER, COURSE-DESC, NUM-CREDITS, GRADE)

8. A Normalization Example
Choose data items
UNF to 1NF
Identify keys
Split groups
Eliminate repeating groups
UNF
1NF
level 1 2
STUDENT-NUMBER,
STUDENT-NAME,
TOTAL-CREDITS,
GPA,
ADVISOR-NUMBER,
ADVISOR-NAME,
COURSE-NUMBER,
COURSE-DESC,
NUM-CREDITS,
GRADE
STUDENT-NUMBER,
STUDENT-NAME,
TOTAL-CREDITS,
GPA,
ADVISOR-NUMBER,
ADVISOR-NAME,
COURSE-NUMBER,
COURSE-DESC,
NUM-CREDITS,
GRADE

9. A Normalization Example
The STUDENT table in 1NF. Notice that the primary key has been expanded to include STUDENT-NUMBER and COURSE-NUMBER. Also, the repeating group has been eliminated.
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10. A Normalization Example
2NF
No attribute dependent on a portion of a primary key
The student name, total credits, GPA, advisor number, and advisor name all relate only to the student number
The course description depends on the course number
Grade field depends on the entire primary key

11. A Normalization Example
Does this attribute depend on the whole of the primary key?
1NF to 2NF
2NF
1NF
STUDENT-NUMBER
STUDENT-NAME
TOTAL-CREDITS
GPA
ADVISOR-NUMBER
ADVISOR-NAME
COURSE-NUMBER
COURSE-DESC
NUM-CREDITS
GRADE
STUDENT-NUMBER,
STUDENT-NAME,
TOTAL-CREDITS,
GPA,
ADVISOR-NUMBER,
ADVISOR-NAME,
COURSE-NUMBER,
COURSE-DESC,
NUM-CREDITS,
GRADE

12. A Normalization Example
You would create a new table for each field and combination of fields in the primary key
STUDENT (STUDENT-NUMBER, STUDENT-NAME, TOTAL-CREDITS, GPA, ADVISOR-NUMBER, ADVISOR-NAME)
COURSE (COURSE-NUMBER, COURSE-DESC, NUM-CREDITS)
GRADE (STUDENT-NUMBER, COURSE-NUMBER, GRADE)

13. A Normalization Example
STUDENT, COURSE, and GRADE tables in 2NF. Notice that all fields are functionally dependent on the entire primary key of their respective tables.
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14. A Normalization Example
3NF
Remove any transitive dependencies
No attribute dependent on a nonkey attribute
The COURSE and GREADE are in 3NF
STUDENT is not in 3NF, because the ADVISOR-NAME field depends on the ADVISOR-NUMBER field, which is not part of the STUDENT primary key
To convert STUDENT to 3NF, you remove the ADVISOR-NAME field from the STUDENT table and place it into a table with ADVISOR-NUMBER as the primary key

15. A Normalization Example
Is this attribute dependent on any other non-key attribute(s)?
2NF
3NF
STUDENT-NUMBER
STUDENT-NAME
TOTAL-CREDITS
GPA
ADVISOR-NUMBER
ADVISOR-NAME
COURSE-NUMBER
COURSE-DESC
NUM-CREDITS
GRADE
STUDENT-NUMBER
STUDENT-NAME
TOTAL-CREDITS
GPA
ADVISOR-NUMBER
ADVISOR-NAME
COURSE-NUMBER
COURSE-DESC
NUM-CREDITS
GRADE

16. A Normalization Example
3NF
Table Names
STUDENT-NUMBER
STUDENT-NAME
TOTAL-CREDITS
GPA
ADVISOR-NUMBER
ADVISOR-NAME
COURSE-NUMBER
COURSE-DESC
NUM-CREDITS
GRADE
STUDENT
ADVISOR
COURSE
GRADE

17. A Normalization Example
3NF
The final 3NF design is
STUDENT (STUDENT-NUMBER, STUDENT-NAME, TOTAL-CREDITS, GPA, ADVISOR-NUMBER)
ADVISOR (ADVISOR-NUMBER, ADVISOR-NAME)
COURSE (COURSE-NUMBER, COURSE-DESC, NUM-CREDITS)
GRADE (STUDENT-NUMBER, COURSE-NUMBER, GRADE)

18. A Normalization Example
ADVISOR
STUDENT
ADVISES
RECEIVES
is on
COURSE
SHOWS
GRADE
Associative entity
The ERD for STUDENT, ADVISOR, and COURSE after normalization

19. A Normalization Example
Compare between the ERD before normalization and after
After normalization we have four entitles: STUDENT, ADVISOR, COURSE, and GRADE, which is an associative entity
You can see that (M:N) relationship between STUDENT and COURSE has been converted into two 1:M relationships
One relationship between STUDENT and GRADE and the other relationship between COURSE and GRADE
You should know that normal forms beyond 3NF exist, but they rarely are used in business-oriented systems

20. Sequence Summary 1NF 2NF 3NF All key attributes defined
No repeating groups in a table
All attributes dependent on a primary key
2NF
No attribute dependent on a portion of a primary key
Attributes may be functionally dependent on nonkey attributes
3NF
Remove any transitive dependencies
No attribute dependent on a nonkey attribute

21. Sequence Summary In this Sequence we have
Explained the three steps of data normalization through an example

22. Reference [1] System Analysis and Design, Sixth Edition
Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt
Publisher: SHELLY CASHMAN SEWIES.