DS-09: Normalisasi Database 1NF 2NF hingga 3NF

Summary

This video explains the concept of database normalization, focusing on the First, Second, and Third Normal Forms (1NF, 2NF, 3NF). It covers the steps involved in transforming a universal table into a normalized structure, eliminating redundancy, and ensuring data integrity. The presenter provides practical examples, demonstrating how to handle issues like repeating groups, non-unique attributes, and transitive dependencies. The video emphasizes the importance of normalization for creating efficient, ideal database designs. Viewers will learn how to apply normalization rules to create well-structured, optimized databases.

Takeaways

• 😀 Normalization is the process of transforming data from a universal or unnormalized table into a structured and efficient database form.
• 😀 First Normal Form (1NF) requires that each attribute in a table is atomic, meaning it cannot contain multiple values or duplicate entries.
• 😀 In 1NF, each row must be unique, and there should be no repeating groups of data, ensuring that all attributes are properly separated.
• 😀 To achieve 1NF, we remove non-atomic values and ensure that no column contains multiple values (e.g., multiple hobbies in one column should be separated).
• 😀 The process of choosing a primary key (PK) is crucial in 1NF, where a composite key might be necessary if one attribute alone is not unique.
• 😀 Second Normal Form (2NF) builds on 1NF by removing partial dependencies, meaning non-primary key attributes must depend fully on the entire primary key.
• 😀 In 2NF, a table is decomposed into smaller tables to ensure that each non-key attribute depends entirely on the full primary key, not just part of it.
• 😀 Third Normal Form (3NF) addresses transitive dependencies, ensuring that non-primary key attributes do not depend on other non-primary key attributes.
• 😀 In 3NF, if any non-primary attribute depends on another non-primary attribute, they must be moved to separate tables to eliminate redundant data.
• 😀 Throughout the normalization process, tables are split, and redundant data is eliminated, which leads to a more efficient and manageable database design.
• 😀 Understanding normalization helps to create a logical and efficient database design, minimizing redundancy and ensuring consistency in data storage.

Q & A

What is normalization in database design?

Normalization is the process of organizing data in a database to reduce redundancy and ensure that the data is stored efficiently without duplication.

What are the different steps in normalization mentioned in the transcript?

The steps in normalization mentioned are: Universal Table, First Normal Form (1NF), Second Normal Form (2NF), and Third Normal Form (3NF).

What is a 'Universal Table' and how does it relate to normalization?

A Universal Table is a form of data representation that is not yet normalized. It contains redundant and repetitive data, making it harder for the system to process efficiently.

What is the main requirement for a table to be in First Normal Form (1NF)?

For a table to be in First Normal Form (1NF), it must have atomic values (no repeating groups or multiple values in one field) and ensure that each row is unique.

What is meant by 'no repeating groups' in the context of 1NF?

No repeating groups means that there should be no columns with multiple values or sets of data in a single field. Each column should contain only a single value.

How do you identify a Primary Key in a table?

A Primary Key is a unique identifier for each record in the table. It must have unique values and cannot be NULL.

Why was a composite key chosen in the example, and how is it formed?

A composite key was chosen because no single attribute (like Project Code) was unique enough to serve as the Primary Key. It combines multiple attributes, such as Project Code and Employee Number, to form a unique key.

What does the Second Normal Form (2NF) ensure?

Second Normal Form (2NF) ensures that all non-key attributes are fully dependent on the entire Primary Key, not just a part of it, and eliminates partial dependencies.

What is meant by 'transitive dependency' and how does it relate to Third Normal Form (3NF)?

A transitive dependency occurs when a non-key attribute depends on another non-key attribute through a third attribute. In 3NF, all non-key attributes must depend only on the Primary Key, not on other non-key attributes.

What is the relationship between attributes like 'Project Title' and 'Employee Number' in 2NF?

In 2NF, attributes like 'Project Title' depend solely on the 'Project Code' and not on the 'Employee Number'. This separation ensures that data is more logically organized and eliminates redundancy.