Normalize Data
Within the context of a relational database, the phrase "data normalization" refers to a set of parameters used in database construction. The intent of normalization is to reduce or eliminate the potential for data redundancy and inconsistent dependencies within a table schema. The "Rules of Normalization" serve as a standardized guideline for structuring the table schema in a relational database to ensure optimal functionality. There are 5 rules for data normalization that are applied to database design in consecutive order: the Zero Form, the Second Form, the Third Form, the Fourth Form and the Fifth Form. Use this article to learn how to apply the 5 Rules of Normalization for effective and efficient database design.
Contents
Steps
Apply the Zero Form Rule for Data Normalization
- Use the Zero Form rule to normalize the data in a relational database. Before the Rules of Normalization have been applied to a table schema, the data is said to be in "Zero Form."
- Apply the Zero Form rule to your table schema. Remove redundancies in a table by dividing recurring groups of data into separate tables and assign a primary key to identify the relationship between each data set.
Apply Second Normal Form Rules for Data Normalization
- Utilize the Second Normal Form rule to normalize the data in a relational database. After the Zero Form rule has been applied, the database is considered to be in the "Second Form."
- Apply the Second Form rule to your table schema to improve the efficiency of a relational database. Relocate values into individual tables when they are associated to more than 1 record, and assign a foreign key to each new table.
Apply Third Form Rules for Data Normalization
- Implement the Third Normal Form rule to normalize a relational database. After the Second Normal Form rule has been applied, the database is considered to be in the "Third Form."
- Apply the Third Normal Form rule to your table schema. Remove any field that does not correlate to the assigned key. By creating a separate table for data that has no relationship with the primary key, the potential for data redundancy is further reduced.
Apply Fourth Normal Form Rules for Database Normalization
- Use the Fourth Normal Form rule for normalizing a relational database. After the Third Normal Form rule has been applied, the database is considered to be in the " Fourth Normal Form." Apply the Fourth Normal Form rule only when the database being designed contains a "many-to-many" relationship.
- Separate independent entities into individual tables when a many-to-many relationship exists within the data set.
Apply Fifth Normal Form Rules for Data Normalization
- Utilize the Fifth Normal Form rule to minimize redundancy of data in a relational database. Like the Fourth Normal Form rule, which is only useful when many-to-many relationships are involved, the Fifth Normal Form rule is generally considered applicable for use with only the most expansive data sets, far exceeding the requirements of the majority of relational databases.
- Reconstruct the original table only from those tables created as a result of its initial deconstruction. Applying the Fifth Normal Form rule ensures that there are no unnecessary columns within the data schema and that each table structure has achieved optimal efficiency in terms of its size.
