Explain The Purpose Of Data Normalization

Explain the purpose of data normalization

Data normalization serves a crucial role in the design and management of relational databases. Its primary purpose is to organize data systematically to reduce redundancy and avoid undesirable characteristics such as insertion, update, and deletion anomalies. By structuring data into well-defined tables and establishing relationships among them, normalization ensures data integrity, consistency, and efficient access. It simplifies the database schema, makes data maintenance easier, and enhances overall database performance.

Development of a simple entity relationship diagram (ERD) normalized to the fifth normal form

Creating an ERD that is normalized to the fifth normal form involves applying a series of normalization rules to eliminate redundancy and dependency anomalies. The process begins with the unnormalized form and proceeds through the first, second, third, Boyce-Codd (BCNF), fourth, and fifth normal forms.

In the context of sales and operational data, the ERD would illustrate entities such as Customer, Sales, Employee, Region, and possibly Product or Part. Each entity contains attributes relevant to its role, with primary keys that uniquely identify each record. Relationships among entities are established to reflect real-world associations, such as a Customer placing Sales, an Employee handling sales transactions, and a Region overseeing certain sales areas.

Normalization to the fifth normal form (5NF) ensures that every join dependency in the schema is implied by the candidate keys, which reduces redundancy to the lowest possible level. At this stage, the ERD may be decomposed into more tables but maintains the integrity and relationships necessary for accurate data representation. An example ERD includes entities and their relationships, clearly defining foreign keys that implement referential integrity.

For this exercise, I have created an ERD using Microsoft Word that depicts the normalized structure of sales and operational data, including entities such as Customer, Employee, Region, Sales, and Sales Details. These entities are interconnected through primary and foreign keys to enforce normalization to the fifth normal form. The diagram emphasizes minimal redundancy and ensures that each dependency is based solely on key relationships, thereby optimizing data consistency and query efficiency.

References

• Codd, E. F. (1970). A Relational Model of Data for Large Shared Data Banks. Communications of the ACM, 13(6), 377-387.