💥Bases de Datos desde Cero. Formas Normales (1FN, 2FN y 3FN).Reload

Introduction

This tutorial aims to explain the basics of database normalization, focusing on the first three normal forms (1NF, 2NF, and 3NF). Understanding these concepts is essential for designing efficient and reliable databases, which are crucial for data integrity and reducing redundancy.

Step 1: Understanding the First Normal Form (1NF)

1NF requires that each column in a table contains atomic values, and each entry in a column must be of the same type. To achieve 1NF:

• Ensure that each column in your table holds indivisible values.
• Avoid repeating groups or arrays within a single column.
• Each table must have a unique identifier (primary key).

Practical Tip

To check if your table is in 1NF, look for any columns that contain multiple values or lists. If you find such columns, consider splitting the data into separate rows or creating related tables.

Step 2: Achieving the Second Normal Form (2NF)

2NF builds upon 1NF and requires that all non-key attributes are fully functionally dependent on the primary key. To achieve 2NF:

• Start with a table that is already in 1NF.
• Identify partial dependencies where a non-key attribute depends only on part of a composite primary key.
• Eliminate these partial dependencies by creating separate tables for these attributes.

Example

If you have a table with a composite key (e.g., StudentID, CourseID) and a non-key attribute that only relies on StudentID (e.g., StudentName), move StudentName to a separate table.

Step 3: Implementing the Third Normal Form (3NF)

3NF requires that a table is in 2NF and that all the attributes are only dependent on the primary key. To achieve 3NF:

• Check for transitive dependencies, where a non-key attribute depends on another non-key attribute.
• Remove these dependencies by creating new tables.

Common Pitfall

Ensure that every non-key attribute is directly related to the primary key. If you find attributes that depend on other non-key attributes, restructure the table to eliminate these dependencies.

Conclusion

In this tutorial, we covered the fundamentals of database normalization, specifically the first three normal forms. By adhering to these principles, you can create more efficient databases that minimize redundancy and enhance data integrity.

Next steps include practicing these normalization techniques on sample datasets or existing databases to solidify your understanding. Consider exploring additional normalization forms beyond 3NF for more complex database designs.