1. Database
Normalization

2. Database
Normalization
What are the problems here?

3. Database Normalization Entity Attributes and their types
Redundant Data
Anomaly and its types
Normalization and its forms

4. Any thing about which data is stored.
Normalization
Entity
Any thing about which data is stored.
Examples:
Person, Company, Event

5. An entity is represented by a set of attributes.
Normalization
Entity
Property of an entity
An entity is represented by a set of attributes.
field

6. Example Attributes Entity STUDENT Student Id Name Address
Phone No
STUDENT
Entity

7. Attribute Types
Simple(component) attributes
Composite attributes
Single-valued attributes
Multi-valued attributes
Derived attributes
Key attributes
Non-Key attributes

8. Which one is Composite Attribute?
Name
First Name
Middle Name
Last Name
Which one is Composite Attribute?

9. Domain The set (range) of allowed values for an attribute
Roll No.
Grade 1 A 2 B 3 F 4 C
Domain for Grade attribute
{ A, B, C, D, F }

10. Redundant Data Employee Table EMPID NAME DEPT SALARY COURSE GRADE 100
Asad
Marketing
42000 IT A
140
Waheed
Accounting
39000
Management B
110
Majid
Info Systems
41500
DBMS

11. An anomaly is an inconsistent or contradictory state of the database.

12. Anomalies Types of Anomalies Insertion Anomaly Deletion Anomaly
Update Anomaly

13. Insertion Anomaly
Occurrence of an error or inconsistency due to the insertion of new data in a table

14. Example Insertion Anomaly
Employee Table
EMPID
NAME
DEPT
SALARY
COURSE
GRADE
100
Asad
Marketing
42000 IT A
140
Waheed
Accounting
39000 …
110
Majid
Info Systems
41500
DBMS
4000
Management B

15. Deletion Anomaly A valid fact is lost when a record is deleted.
Occurrence of an error or inconsistency due to the deletion of data in a table
A valid fact is lost when a record is deleted.

16. Example Deletion Anomaly
Employee Table
EMPID
NAME
DEPT
SALARY
COURSE
GRADE
100
Asad
Marketing
42000
SPSS A
Management B
140
Waheed
Accounting
39000
110
Majid
Info Systems
41500
Intro. to IT

17. Update Anomaly One occurrence of a fact is changed,
Occurrence of an error or inconsistency due to the modification of data in a table
One occurrence of a fact is changed,
but not all occurrences.

18. Example Update Anomaly
Employee Table
EMPID
NAME
DEPT
SALARY
COURSE
GRADE
100
Asad
Marketing
42000
SPSS A
140
Waheed
Accounting
39000 …
110
Majid
Info Systems
41500
Intro. to IT B
45000
Management

19. Normalization Basic Idea 1. Divide a table into two or more tables and
2. Define relationships between the tables.
Objectives
Minimize data duplication
Efficient data retrieval
Less space
Less errors

20. Normalization
Two basic conditions
No redundant data
No anomalies.

21. 1st three levels often used
Normal Forms 7
Levels / Stages of normalization
1st three levels often used

22. 7 Normal Forms Unnormalized data Normalized data 1NF 2NF 3NF BCNF 4NF
5NF (PJNF)
DKNF
Normalized data

23. Steps in normalization
Remove
Table with repeating groups
Repeating Groups
1st Normal Form
Partial Dependencies
2nd Normal Form
Transitive Dependencies
3rd Normal Form
Determinant / Candidate Keys
Boyce-Codd Normal Form
Multivalued Dependencies
4th Normal Form
Removing Remaining anomalies
5th Normal Form (Project Join NF)
Removing Remaining anomalies
Domain Key Normal Form

24. Result Card Card No.: 1 Issue date: 3/4/8
Example
Card No.: 1
Issue date: 3/4/8
Student ID: Student Name: ABC
Student Address: 45-C, Lahore.
Course ID
Course Name
Total Marks
Obtained Marks
101 W
100 70
102 X 50
103 Y 80
104 Z 60
1st
Grand Total: 260
Representation

25. Before Normalization Redundant Data 2nd Representation Crd_No Is_Date
S_ID
SName
Addr
C_ID
C_Name
TMrks
OMrks
GTtl 1
3/4/8
111
ABC
45-C
101 W
100 70
260
102 X 50
103 Y 80
104 Z 60 2 95
MNO
40-D
230 …
Redundant Data
2nd
Representation

26. There are no repeating attribute-groups.
Normal Form
1st
There are no repeating attribute-groups.

27. Before Normalization Best Approach 3rd Representation 1 3/4/8 111 ABC
CrdNo
IsDate
SId
SName
Adr
CId
CName
TMrks
OMrks
GTtl 1
3/4/8
111
ABC
45C
101 W
100 70
102 X 50
103 Y 80
260 2 95
MNO
40D
104 Z 60
230 …
Best Approach
3rd
Representation

28. Before Normalization 4th Representation Crd_No Is_Date S_ID SName Addr
C_ID
C_Name
TMrks
OMrks
GTtl 1
3/4/8
111
ABC
45-C
101 W
100 70
260
102 X 50
103 Y 80
104 Z 60 2 95
MNO
40-D
230 …
Crd_No
Is_Date
S_ID
SName
Addr
C_ID
C_Name
TMrks
OMrks
GTtl 1
3/4/8
111
ABC
45-C
101 W
100 70
260 2 95
MNO
40-D
103 Y
230 …
102 X
100 50
103 Y
100 80
104 Z
100 60
104 Z
100 60
4th
Representation

29. Normal Form
1st
Process
Identify the primary key of denormalized table.
Repeating attribute-groups of the table are separated out in form of a new table.
Primary key of old table is added into new table as foreign key.
Identify the primary key of new table.

30. Repeating Attributes Card No.: 1 Issue date: 3/4/8
Student ID: Student Name: ABC
Student Address: 45-C, Lahore.
Course ID
Course Name
Total Marks
Obtained Marks
101 W
100 70
102 X 50
103 Y 80
104 Z 60
Grand Total: 260
Repeating attribute-groups

31. Repeating Attributes Grand Total: 260 5th Card No.: 1
Issue date: 3/4/8
Student ID: Student Name: ABC
Student Address: 45-C, Lahore.
Course ID
Course Name
Total Marks
Obtained Marks
101 W
100 70
Course ID
Course Name
Total Marks
Obtained Marks
102 X
100 50
Course ID
Course Name
Total Marks
Obtained Marks
103 Y
100 80
Course ID
Course Name
Total Marks
Obtained Marks
104 Z
100 60
5th
Grand Total: 260
Representation

32. } Normal Form 1st Card No PK Issue Date Student ID Student Name
Student Address
Grand Total
Card No FK
Course ID
Course Name
Total Marks
Obtained Marks } CP
Table-2
Table-1

33. } Normal Form 1st Card No PK Issue Date Student ID Student Name
Student Address
Grand Total
Card No FK
Course ID
Course Name
Total Marks
Obtained Marks } CP
Table-2
Table-1

34. There is no partial dependency.
Normal Form
2nd
There is no partial dependency.
part  partial
Partial dependency:
An attribute depends upon the part of the key, but not on the whole key.

35. Normal Form 2nd Relation is in 1NF.
Conditions
Relation is in 1NF.
All non-key attributes should depend upon Key attribute.
Implementable if Compound Key Exist.

36. Normal Form
2nd
Process
All non-key attributes that depend upon part of key are separated out in a new table along with part of key on which these attributes depend.
Identify the primary key of new table and add it back to the old table as foreign key.

37. } Normal Form 2nd Card No FK Course ID CP Course Name Total Marks
Obtained Marks } CP

38. }CP } Normal Form 2nd Card No FK Course ID Course Name Total Marks
Obtained Marks } CP
}CP
Card No FK
Course ID FK
Obtained Marks
Course ID PK
Course Name
Total Marks

39. There is no transitive dependency.
Normal Form
3rd
There is no transitive dependency.
Transitive dependency:
A non-key attribute depends upon another non-key attribute.

40. Normal Form 3rd Relation is in 2NF.
Conditions
Relation is in 2NF.
All non-key attributes depend on key attribute.

41. Normal Form
3rd
Process
All non-key attributes depending on any non-key attribute are separated out in form of new table.
Identify the primary key of new table and add it back to the old table as foreign key.

42. Normal Form 3rd Card No PK Issue Date Student ID FK Card No PK
Grand Total
Card No PK
Issue Date
Student ID
Student Name
Student Address
Grand Total
Student ID PK
Student Name
Student Address
Any thing wrong here?

43. }CP Normalization Over all Result Card No FK Course ID FK
Obtained Marks
}CP
Card No PK
Issue Date
Student ID FK
Grand Total
Student ID PK
Student Name
Student Address
Course ID PK
Course Name
Total Marks

44. Invoice Practice Exercise Invoice no.: 1 Invoice date: 3/4/8
Customer ID: Customer Name: ABC
Customer Address: 45-C, Lahore Phone :
P_ID
P_Name
QTY
Price
Total
101 W 3 20 60
102 X 2 10
103 Y 30
104 Z 1
Invoice Total: 200