This document discusses database normalization. It defines normalization as organizing data to eliminate redundant data and ensure data dependencies. The main goals are isolating data, reducing storage space, and making the database structure flexible. The document outlines the various normal forms from 1st normal form to Boyce-Codd normal form. It provides examples of transforming data from an unnormalized form to higher normal forms using a student database example.

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3. NORMALIZATION IN DATABASES
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4. NORMALIZATION
• The process of efficiently organizing data in a
database.
• Two goals of normalization process:
 Eliminating Redundant Data
 Ensuring data dependencies
• Main objective:
 Isolate data
 Reduce the amount of database space
 Make database structure flexible
 Consistent throughout database

5. • Should not suffer from following anomalies.
 Update anomalies.
 Insertion anomalies.
 Deletion anomalies.
S_No S_name S_address Course_opted
1 smith calicut php
2 turner kannur java
3 clark wayanad java
4 smith calicut Android

6. Normalization Stages
• 1NF
• 2NF
• 3NF
• Boyce-Codd Normal Form (BCNF or 3.5NF)

7. First Normal Form (1NF)
• The values in each column of a table are
atomic .
• Each table has a primary key.
• There are no repeating groups.

8. Second Normal Form (2NF)
• Should be in 1NF.
• Remove subsets of data that apply to multiple
rows of a table and place them in separate
tables.
• Create relationships between tables.

9. Third Normal Form (3NF)
• should be 2NF.
• Has no transitive functional dependencies.
• Remove columns that are
not dependent upon the primary key.
• To convert 2NF to 3NF, we again divide tables.

10. Boyce-Codd Normal Form(BCNF)
• Should be 3NF.
• Every determinant must be a candidate key.
• All tables can have only one primary key
• Candidate Key:
 Any attribute or a set of attributes together that
has the eligibility to become a primary key.

11. TRANSFORMATION FROM UNF TO
HIGHER NORMAL FORMS USING AN
EXAMPLE
Dep_no Dep_
name
Stud_no Stud_
name
Stud_
dob
Stud_
age
Course_
name
Course_
fee
1 cse 101 Name 1 1990-1-01 23 java 5000
102 Name 2 1991-5-25 22 php 4000
103 Name 3 1992-3-01 21 Java,php 5000,
4000
2 ec 104 Name 4 1990-2-01 23 robotics 10000
105 Name 5 1991-3-01 22 circuits 15000
106 Name 6 1992-4-01 21 robotics 10000

12. Conversion to 1st Normal Form
Dep_no Dep_
name
Stud_no Stud_
name
Stud_
dob
Stud_
age
Course_
name
Course_
fee
1 cse 101 Name 1 1990-1-01 23 java 5000
1 cse 102 Name 2 1991-5-25 22 php 4000
1 cse 103 Name 3 1992-3-01 21 Java 5000
1 cse 103 Name 3 1990-2-01 21 php 4000
2 ec 104 Name 4 1991-3-01 23 robotics 10000
2 ec 105 Name 5 1992-4-01 22 circuits 15000
2 ec 106 Name 6 1990-1-01 21 robotics 10000

13. Conversion to 2nd Normal Form
Dep_no Dep_name
1 cse
2 ec
Fk_dept_id Fk_stud_id Course_name Course_fee
1 101 java 5000
1 102 php 4000
1 103 Java 5000
1 103 php 4000
2 104 robotics 10000
2 105 circuits 15000
2 106 robotics 10000
Stud_no Stud_name Stud_dob Stud_age
101 Name 1 1990-1-01 23
102 Name 2 1991-5-25 22
103 Name 3 1992-3-01 21
103 Name 3 1990-2-01 21
104 Name 4 1991-3-01 23
105 Name 5 1992-4-01 22
106 Name 6 1990-1-01 21

14. Course_
name
Course_
fee
java 5000
php 4000
robotics 10000
circuits 15000
Dep_no Dep_
name
1 Cse
2 ec
Fk_dept_no Fk_Stud_no Fk_Course_name
1 101 java
1 102 php
1 103 Java
1 103 php
2 104 robotics
2 105 circuits
2 106 robotics
Stud_no Stud_name Stud_dob
101 Name 1 1990-1-01
102 Name 2 1991-5-25
103 Name 3 1992-3-01
103 Name 3 1990-2-01
104 Name 4 1991-3-01
105 Name 5 1992-4-01
106 Name 6 1990-1-01
Conversion to 3nd Normal Form

15. Conversion To BCNF

16. Class_name Roll_no name Class_teacher
Class a 1 smith Teacher a
Class a 2 turner Teacher a
Class b 1 clark Teacher b
Class c 1 allen Teacher c
Class_name Class_teacher
Class a Teacher a
Class b Teacher b
Class c Teacher c
Class_name Roll_no name
Class a 1 smith
Class a 2 turner
Class b 1 clark
Class c 1 allen
A Case where The table is in 3NF but not in BCNF
A Case where The table is in both in 3NF and BCNF

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