Database Normalization

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Normalization is a mathematical approach that helps to decompose a complex Relation (Rx) into multiple simplex Relations (R1, R2, R3 ... Rn), based on Functional Dependencies and Keys. E.F. Codd was implemented Normalization Technique in the Relational Database Model to design Relational Database Structure.

Normalization Technique is used to eliminate data insertion, data update and data deletion anomalies, minimize data redundancy, minimize data storage memory, improve data integrity and simplify the database query process in the Relational Database Model.

Database operation is affect, when add, edit or delete records in the inadequate normalized table is called Database Anomalies. Anomaly Problem can be categories into Insert Anomaly, Update Anomaly and Delete Anomaly.

Insert Anomaly is happen when add record(s) into inadequate quantity of attributes table structure. An instance, a record is hold 15 information and the table is designed with 13 attributes. When insert new record(s), the database operation is affect and occur error.

Update Anomaly is happen when update record(s) into inadequate normalized and redundant records. An instance, an employee table structure does not have primary key to identify unique record and duplicate employee information stored in the particular table. When, update particular employee information, the database operation is affect and update wrong information.

Delete Anomaly is happen when delete record(s) into inadequate normalized and redundant records. An instance, an employee table structure does not have primary key and foreign key to identify unique record and duplicate employee information stored in the particular table. When, delete particular employee information, the database operation is affect and delete wrong information.

Initially, E.F. Codd was introduced First Normal Form (1NF), Second Normal Form (2NF) and Third Normal Form (3NF) based on Single-Valued Functional Dependency and Keys. Raymond F. Boyce and E.F. Codd were enhanced Third Normal Form (3NF) and introduced Boyce Codd Normal Form (BCNF).

Later, Ronald Fagin was introduced Forth Normal Form (4NF) and Fifth Normal Form (5NF) based on Multi-Valued Dependency and Join Dependency. Ronald Fagin was introduced Domain-Key Normal Form (DKNF) based on Domain and Key Integrity Constraints.

Finally, C.J. Date, Hugh Darwen and Nikos Lorentzos were introduced Sixth Normal Form (6NF) based on Join Functional Dependency, Generalized Join Operator and Keys.

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