What is the Difference Between 1NF and 2NF and 3NF?

The difference between 1NF, 2NF, and 3NF lies in the degree of data normalization, which is a process that organizes data to reduce redundancy and improve data integrity. Here's a brief explanation of each normal form:

1. First Normal Form (1NF):

• A relation is in 1NF if it contains only atomic values (values that cannot be further divided).
• Each column in a 1NF table should contain only one value for each row.

1. Second Normal Form (2NF):

• A relation is in 2NF if it is in 1NF and all non-key attributes are fully functionally dependent on the primary key.
• In other words, a table is in 2NF if it has no partial dependency, meaning all non-key attributes are fully dependent on the primary key.

1. Third Normal Form (3NF):

• A relation is in 3NF if it is in 2NF and no transition dependency exists.
• For a table to be in 3NF, it must be in 2NF and have no transitive partial dependency, meaning no non-prime attribute (an attribute that is not part of the candidate key) is dependent on another non-prime attribute.

In summary, 1NF focuses on removing repeating groups and ensuring atomic values, 2NF eliminates redundancy and partial dependency by making non-key attributes fully dependent on the primary key, and 3NF goes a step further by eliminating transitive partial dependency.

Comparative Table: 1NF vs 2NF vs 3NF

Here is a table comparing the differences between First Normal Form (1NF), Second Normal Form (2NF), and Third Normal Form (3NF):

Here's a brief explanation of each normal form:

• 1NF: Ensures that each table cell contains only one value, and each column in a table is unique. It removes repeating groups but does not handle redundancy or update anomalies.
• 2NF: Eliminates redundancy by ensuring that all non-key attributes are fully dependent on the primary key. It handle update anomalies, but not indirect dependencies between attributes.
• 3NF: Removes indirect dependencies between non-key attributes, ensuring that no non-key attribute depends on another non-key attribute. It builds upon the constraints of 1NF and 2NF, resulting in a more efficient and reliable database.