The document discusses database normalization. It defines normalization as a process of evaluating and correcting table structures to minimize data redundancies and anomalies. The normalization process involves converting tables to first, second, and third normal forms through removing partial and transitive dependencies. Higher normal forms like 3NF are better than 2NF and 1NF as they restrict relation formats and reduce vulnerabilities to update, delete, and insert anomalies.

1. E R M O D E L L I N G & D B N O R M A L I Z A T I O N
DATABASE NORMALIZATION

2. NORMALIZATION
 Process for evaluating and correcting table structures to
minimize data redundancies
 Reduces data Anomalies
 Brings a database to a consistent state
 Works through a series of stages called normal forms:
 First normal form (1NF)
 Second normal form (2NF)
 Third normal form (3NF)
The higher you go the better 3rd normal form is better than 2  2 is
better than 1

3. REASONS FOR NORMALIZATION
 Data Redundancy

4. RESONS FOR NORMALIZATION
 Relations become progressively more restricted (stronger)
in format and also less vulnerable to update anomalies.
 One peace of information is stored in one location / place

5. KEYWORDS
 Determinant  determines the value of other attributes
in the tuples.
 Functional Dependency Describes relationship
between attributes in a relation.

6. EXAMPLE OF DATABASE ANOMALIES
 Update Anomalies
 Delete Anomalies
 Insert Anomalies

7. UPDATE ANOMALIES
 Occurs when data is scattered
 Not linked together properly
 Leaves database inconsistent

8. DELETE ANOMALIES
 Parts of data not deleted
 Unawareness

9. INSERT ANORMALIES
 Insert Data in a record that does not exist

10. FIRST NORMAL FORM
 All attributes in a relation must have atomic
domains
 Purpose is to remove repeating groups in relation
 Each row and column contains one and only one
value
 Gets rid of extra , make data as small as it can get
 All key attributes are defined
 No repeating column

11. FIRST NORMAL FORM
 Rearrange the table to convert to First normal form
Each
attribute
must
contain
only one
single
value
form its
predefine
d
domain.

12. EXAMPLE 2
 What's the wrong with the table?

13. COLUMNS REMOVED
 1st Normal form
Primary Key

14. SECOND NORMAL FORM
 Remove partial dependencies
 Every non-primary-key attribute is fully functionally dependent
on the primary key.
 No attribute is dependent on only a portion of primary key
 Key Terms
 Prime Attribute  An attribute which is part of
primary key.
 Non Prime Attribute  Any attribute which is not
part of the primary key.
 Every Non-Prime attribute SHOULD be fully
functionally dependent on the prime key attribute.
 In short Non key attributes should depend on full
primary key

15. EXAMPLE
 .

16. EXAMPLE ..SECOND NORM
 The relation is broken into two thereby removing
partial dependency.

17. EXAMPLE 2
 Person Project

18. CONTINUATION 2ND NORM
 .

19. THIRD NORMAL FORM
 All non key attributes should nontransitively
dependent on the primary key.

20. RESULT
 .