The document discusses database normalization. It defines normalization as the process of organizing data to minimize redundancy and eliminate anomalies. It describes several normal forms including 1NF, 2NF, 3NF, and BCNF. The goal of normalization is to organize data into tables and links between tables to reduce duplication and ensure data integrity through various normal forms.

1. DEPARTMENT OF COMMERCE WITH FINANCE
NORMALIZATION in DBMS
Dr.SNS RAJALAKSHMI COLLEGE OF ARTS AND SCIENCE
COIMBATORE-49
(AUTONOMOUS)
Accredited by NAAC (Cycle-III) with ‘A+’ Grade

2. Introduction
Normal Forms
Anomalies in DBMS
Types of Normal Forms
Conclusion

3.  Normalization is the process of organizing the data in
the database.
 Normalization is used to minimize the redundancy from
a relation or set of relations. It is also used to eliminate
the undesirable characteristics like Insertion, Update
and Deletion Anomalies.
 Normalization divides the larger table into the smaller
table and links them using relationship.
 The normal form is used to reduce redundancy from
the database table.

4.  Edgar Codd proposed the theory of normalization of
data with First Normal Form and extending the theory
with Second and Third Normal Form.
 Later he joined Raymond F. Boyce to develop the
theory of Boyce-Codd Normal Form.
 By using different normal forms we can remove all these
anomalies and bring the database to a consistent state.

5. Stu_id Stu_name Stu_add Course_co
de
1001 shiva cbe 219
1002 arul chennai 218
1001 shiva cbe 218
1003 vijay ooty 219
krishna kerela 220
1005 reva Kodai 221
 Update anomalies
 Deletion anomalies
 Insert anomalies
Fees not
Paid
Deleting a
course code
will delete
the data

6. 1NF
2NF
3NF
BCNF
• It contains an atomic value
• Non-key attributes are fully
functional dependent on the
primary key.
• No transition dependency
exists.
•It has no multi-valued
dependency.

7.  A relation will be 1NF if it contains an atomic value.
 It states that an attribute of a table cannot hold multiple
values. It must hold only single-valued attribute.
 First normal form disallows the multi-valued attribute,
composite attribute, and their combinations.
id name phone add
101 hari 247859,
248795
cbe
102 lali 248964 ooty
id name phone add
101 hari 247859, cbe
101 hari 248795 cbe
Before 1NF After 1NF

8.  In the second normal form, all non-key
attributes are fully functional dependent on the
primary key.
id sub
101 maths
101 che
102 social
103 tamil
id sub age
101 maths 40
101 che 40
102 social 28
103 tamil 30
id name
101 40
101 40
102 28
103 30

9.  A relation will be in 3NF if it is in 2NF and not
contain any transitive partial dependency.
 3NF is used to reduce the data duplication. It is
also used to achieve the data integrity.
 If there is no transitive dependency for non-prime
attributes, then the relation must be in third
normal form.

10. emp_id emp_name emp_zip emp_state emp_city
emp_distri
ct
1001 John 282005 UP Agra Dayal Bagh
1002 Ajeet 222008 TN Chennai M-City
1006 Lora 282007 TN Chennai
Urrapakka
m
1101 Lilly 292008 UK Pauri Bhagwan
emp
_id
emp_
name
emp_zip
1001 John 282005
1002 Ajeet 222008
1006 Lora 282007
1101 Lilly 292008
emp_id emp_state
emp_cit
y
emp_dis
trict
1001 UP Agra
Dayal
Bagh
1002 TN Chennai M-City
1006 TN Chennai
Urrapakk
am
1101 UK Pauri Bhagwan

11.  BCNF is the advance version of 3NF. It is stricter than
3NF.
 A table is in BCNF if every functional dependency X → Y,
X is the super key of the table.
emp_id emp_country
emp_
Dept
Dept_Type
emp_dept
no
1001 India 245 design 801
1001 India 521 test 541
1002 Africa 654 store 654
1002 Africa 245 maintain 254

12.  Emp_country table:
emp_id emp_country
1001 India
1001 India
EMP_DEPT table:
emp_Dept
Dept_Ty
pe
emp_dept
no
245 design 801
521 test 541
654 store 654
245 maintain 254
EMP_DEPT_MAPPING table:
emp_id emp_Dept
1001 245
1001 521
1002 654
1002 245