What are the benefits and drawbacks of using third normal form (3NF) for database design?

2 What are the normal forms?

Normal forms are the levels or stages of normalization that a database can achieve. Each normal form has a set of criteria or conditions that the database must meet to be considered normalized. The higher the normal form, the more normalized the database is, but also the more complex and difficult it is to design and maintain. The most common normal forms are the first normal form (1NF), the second normal form (2NF), and the third normal form (3NF).

3 What is 1NF?

The first normal form (1NF) is the most basic level of normalization. It requires that each table has a primary key, which is a unique identifier for each row, and that each column contains atomic values, meaning that they cannot be further divided into smaller parts. For example, a column that stores names should not contain both first and last names, but rather separate columns for each. 1NF also requires that there are no repeating groups or arrays of values in a single column, such as a list of phone numbers or hobbies.

4 What is 2NF?

The second normal form (2NF) builds on 1NF and adds another condition: that each table has only one purpose or theme, and that each column is fully dependent on the primary key. This means that there are no partial dependencies, meaning that a column depends on only part of the primary key, or transitive dependencies, meaning that a column depends on another column that is not the primary key. For example, a table that stores customer orders should not contain columns that store customer details, such as address or email, as they are not related to the order itself, but rather to the customer.

5 What is 3NF?

The third normal form (3NF) builds on 2NF and adds another condition: that each table has no columns that are derived or calculated from other columns. This means that there are no functional dependencies, meaning that a column can be computed from another column using a formula or a function. For example, a table that stores product prices should not contain a column that stores the total price with tax, as it can be calculated from the base price and the tax rate.

6 What are the benefits and drawbacks of using 3NF for database design?

Using 3NF for database design has its advantages and disadvantages. Benefits include reduced data redundancy and storage space, prevention of data anomalies and improved query performance. However, drawbacks include increased complexity in database design, more joins and subqueries to retrieve data, and a lack of reflection of business logic or real-world scenarios.