What is the first normal form in SQL?

Normal form

Normal form or normalization is used to reduce the redundancy from a relation.

In normalization, we divide the larger tables into smaller ones.

First normal form

If a relation contains an atomic value, it is said to be in the first standard form.

• First normal form states that we cannot have multiple values for the same attribute in a table.

• One table only should have a single-valued attribute in the first standard form.

Explanation

• In the table above, we have the Name attribute as a multi-value attribute, which violates the first normal form.

• Hence, we must decompose the table into two smaller tables to follow the first standard form.

• Decomposition is carried out so that we can get the required table that follows the first normal form.

• The “Master table” is decomposed into two smaller tables to meet our criteria.

• After we decompose the table, the multi-valued attribute is split into single-value attributes.