1. SEEM3430: Information Systems Analysis and Design
ERD: Normalization
SEEM3430: Information Systems Analysis and Design

2. Data Normalization
Organize data attributes in the logical data model so that they are grouped in a stable and flexible manner.
Based on the functional dependence concept.

3. Functional Dependency
Relationship between two attributes
For any relation R, attribute B is functionally dependent on attribute A if, for every valid instance of A, that value of A uniquely determines the value of B.

4. A relation is in 1NF if it contains no repeating data elements.
Normal Form
Description
First Normal Form (1NF)
A relation is in 1NF if it contains no repeating data elements.
Second Normal Form (2NF)
A relation is in 2NF if it is in 1NF and contains no partial functional dependencies.
Third Normal Form (3NF)
A relation is in 3NF if it is in 2NF and contains no transitive dependencies.
Table 6-6. The Three Common Normalized Forms

5. First Normal Form (1NF) Contains no repeating elements
any entity that contains one or more multivalued attributes must be transformed
Figure 6-10

6. Figure 6-10. The Three Common Normalized Forms

7. Second Normal Form (2NF)
A relation is in 1NF and it contains no partial functional dependencies.
Partial functional dependency exists when one or more of the nonkey attributes can be defined by less than the full primary key.

8. Figure 6-11. Second Normal Form

9. Third Normal Form (3NF)
A relation is in 2NF and no transitive dependencies exist.
Transitive Dependency: when one or more nonkey attributes can be derived from one or more other nonkey attributes

10. Figure 6-12. Third Normal Form

11. The fully Normalized ERD
Shows all the entities, their attributes, and their relationships to all other entities.
From the logical data model, the physical model of the database can be easily constructed.