Relational databases are widely used, and their structure should be as user-friendly as possible.

• Normalization is a process of converting the database structure to a normal form.
• Normal forms are certain rules for building quality databases.

Normalization and normal forms refer to relational databases.

The normalized database is very comfortable to use and query-friendly, and helps to miss many problems.

Normal forms

There are 8 normal forms:

• First normal form
• Second normal form
• Third normal form
• Boyce–Codd normal form
• Fourth normal form
• Fifth normal form
• Domain-key normal form
• Sixth normal form

Note

You can see six numbered normal forms and two normal forms with more specific names. That is why programmers say that there are 6+2 normal forms.

What problems does normalization solve?

Normalization helps improve the database structure by reducing redundancy, inconsistencies, and anomalies in data. Each normal form helps to achieve a more efficient database that is easy to query and maintain. Normalization facilitates the execution of CRUD operations (Create, Read, Update, and Delete) and enables simpler and more accurate data retrieval.

A highly normalized database can increase efficiency in terms of storage, performance, and accuracy of the data. It also provides flexibility to make changes to the database schema without affecting the data integrity.

A detailed description of each normal form can be found in the next chapters.

What problems can normalization cause?

Normalization is an essential part of database design that helps eliminate redundancies and inconsistencies in data. However, it can also cause some problems.

When a database is over-normalized, it can lead to performance issues as more joins may be required to retrieve data. This can result in slower query execution times, especially for large databases.

Furthermore, normalization can sometimes make it more difficult to insert or update data, as the data may be spread across multiple tables. This can make the database schema more complex and difficult to understand, especially for non-expert users.

While it is important to normalize databases, it is also important to strike a balance between normalization and performance. In practice, most databases are normalized to a certain extent (usually up to the third normal form), but not completely, in order to maintain a reasonable level of performance and usability.