First Normal Form (1NF)

It is the most basic level of database normalization. A table is in 1NF if it meets the following criteria:

• Atomic Values: All the columns should contain atomic (indivisible) values, meaning each cell in the table should hold a single value. No multiple values (like a list) in a single cell.
• No Repeating Groups: There should be no repeating groups or arrays in the table. Each piece of data should be stored in a separate row and column.

Example of a Table Not in 1NF

OrderID CustomerName    PizzaSize   Toppings
001 Alice   Medium  Pepperoni, Mushrooms
002 Bob Large   Sausage, Olives
003 Charlie Small   Pepperoni

Issues:

The Toppings column contains multiple values (e.g., "Pepperoni, Mushrooms"), which violates 1NF because each cell should have only a single, atomic value.

Transforming to 1NF
To bring this table into 1NF, we need to ensure that each cell contains a single value:

Summary

A table is in 1NF when:

• Each column contains atomic, indivisible values.
• There are no repeating groups or arrays within rows.
• 1NF helps ensure data consistency by breaking down data into the smallest meaningful units, making it easier to search, sort, and manage.