Normalisasi Basis Data 1NF, 2NF, 3NF dan Contoh Kasus Sederhana

P Indah Ciptayani

7 Oct 202112:02

Summary

TLDRThis video script discusses the concept of normalization in database management, a process used to organize attributes or columns within a table to minimize duplicate data and ensure consistency. It explains the different forms of normalization, starting from the first normal form (1NF) where each cell contains a single value, to the third normal form (3NF), which eliminates transitive dependencies. The script guides viewers through the steps of normalization, using examples to illustrate how to identify and resolve partial and transitive dependencies, ultimately aiming to achieve a well-structured database free from anomalies.

Takeaways

😀 Normalization is a process used to organize attributes or columns in a table to ensure a well-structured database with minimal duplicate data.
🔑 The ideal structured table should contain data with minimal duplication, aiming for the absence of duplicate data if possible.
🔍 Normalization involves breaking down tables into simpler forms to eliminate redundancy and ensure consistency, starting from the first normal form (1NF) to the third normal form (3NF).
📚 Understanding functional dependencies is crucial for proper normalization, as it helps identify how data should be structured to avoid anomalies.
🚫 Anomalies in data, such as insert, update, and delete issues, can occur if tables are not normalized properly, leading to inconsistent and unreliable data.
📈 The first normal form (1NF) requires that each cell in a table contains a single value, ensuring atomicity and no multi-valued attributes.
🔄 The second normal form (2NF) builds on 1NF by eliminating partial dependencies, where non-key attributes are dependent on only a part of a composite key.
🔄 The third normal form (3NF) further refines the structure by removing transitive dependencies, ensuring that non-key attributes are only dependent on the primary key.
📝 The process of normalization involves checking the current state of a table, applying rules to achieve 1NF, then 2NF by removing partial dependencies, and finally 3NF by eliminating transitive dependencies.
🔍 Examples and case studies are essential for understanding normalization, as they provide practical scenarios to apply the concepts and rules of database normalization.

Q & A

What is normalization in the context of database management?
-Normalization is a process used to organize attributes or columns in a table to structure the database well, minimizing duplicate data and ensuring consistency.
Why is it important to minimize duplication in a database?
-Minimizing duplication is important to avoid redundancy and maintain data integrity, which simplifies updates and reduces storage space.
What are the different forms of normality in normalization?
-There are several forms of normality, starting from unnormalized to first normal form (1NF), second normal form (2NF), third normal form (3NF), Boyce-Codd normal form (BCNF), and fifth normal form (5NF).
What is the first step in the normalization process?
-The first step is to check if the table is in 1NF, which means each cell contains only a single value and there are no repeating groups.
How do you identify partial dependencies in a table?
-Partial dependencies are identified by checking if any non-prime attribute is dependent on a part of the primary key, rather than the whole key.
What is the purpose of moving to 2NF in normalization?
-The purpose of 2NF is to eliminate partial dependencies, ensuring that all non-prime attributes are fully functionally dependent on the primary key.
What is a transitive dependency and why is it a concern in normalization?
-A transitive dependency is when an attribute is dependent on another non-key attribute. It's a concern because it can lead to anomalies and is removed in 3NF.
How can you tell if a table is in 3NF?
-A table is in 3NF if it is in 2NF and has no transitive dependencies, meaning there are no dependencies between non-key attributes.
What is the significance of understanding dependencies when normalizing a database?
-Understanding dependencies is crucial for proper normalization because it helps identify and eliminate anomalies and redundancies, leading to a more efficient and consistent database structure.
Can you provide an example of how to break down a table to achieve 3NF?
-An example would be to take a table with a composite key and separate it into multiple tables where each non-key attribute is dependent only on the primary key, thus eliminating transitive dependencies.

Outlines

00:00

📚 Introduction to Normalization

The paragraph introduces the concept of normalization in database management. Normalization is a process that organizes attributes or columns in a table to ensure a well-structured database. The ideal structured table should contain minimal duplicate data. The speaker explains that normalization aims to reduce data redundancy and anomalies, leading to consistent data. The explanation includes the different forms of normalization, starting from unnormalized to the first normal form (1NF), second normal form (2NF), third normal form (3NF), and beyond, with a focus on understanding dependencies and anomalies to achieve a normalized database.

05:02

🔍 Achieving Second Normal Form (2NF)

This section delves into the process of achieving the second normal form (2NF) in database normalization. The speaker explains that to reach 2NF, partial dependencies must be eliminated. The explanation involves identifying the primary key and understanding which non-key attributes are dependent on it. The example given involves a student database with attributes like NIM, student name, major, and department. The process involves creating separate tables for students and courses to remove partial dependencies, resulting in a more normalized structure. The speaker also discusses how to identify and resolve anomalies that may still exist after attempting to achieve 2NF.

10:02

🛠️ Moving Towards Third Normal Form (3NF)

The final paragraph focuses on the steps to achieve third normal form (3NF). The speaker discusses the concept of transitive dependency and how it can lead to anomalies if not addressed. The example continues with the student database, explaining how to identify and remove transitive dependencies. The process involves further splitting the tables to ensure that each table only contains data that is directly related to its primary key, thus eliminating any non-key attributes that do not depend on the entire primary key. The result is a set of tables that are in 3NF, with each table having a clear relationship defined by its primary key and no transitive dependencies remaining.

Mindmap

Keywords

💡Normalization

Normalization is a database design process used to organize data to reduce redundancy and improve data integrity. In the context of the video, normalization is described as a method to structure tables by grouping attributes or columns effectively. The video emphasizes that a well-structured table should minimize duplicate data, which aligns with the ideal of normalization where the database tables are not interrelated in a way that causes data redundancy.

💡Dependencies

Dependencies, or dependenci, refer to the relationships between different data elements within a database. The video script discusses the importance of understanding functional dependencies to correctly apply normalization rules. Dependencies are crucial for determining how data should be organized to avoid anomalies and ensure consistency across the database.

💡First Normal Form (1NF)

First Normal Form (1NF) is the initial step in the normalization process where a table is structured such that each cell contains a single value, and there are no repeating groups or arrays. The video script uses the term to describe the condition where each row and column intersection contains only one value, which is a fundamental requirement for a table to be considered in 1NF.

💡Partial Dependency

Partial Dependency is a term used to describe a situation where a non-key attribute is dependent on only a part of a composite key. The video script explains that to achieve the Second Normal Form (2NF), partial dependencies must be eliminated. This is illustrated in the script with examples of how to break down tables to remove such dependencies.

💡Second Normal Form (2NF)

Second Normal Form (2NF) is a level of database normalization that builds upon 1NF by eliminating partial dependencies. A table is in 2NF if it is in 1NF and every non-key attribute is fully functionally dependent on the primary key. The video script discusses how to identify and remove partial dependencies to achieve 2NF.

💡Transitive Dependency

Transitive Dependency occurs when an attribute is dependent on another attribute that is not a prime attribute or part of the primary key. The video script mentions that to reach the Third Normal Form (3NF), transitive dependencies must be removed. This ensures that there are no indirect dependencies that could lead to anomalies in data insertion, update, or deletion.

💡Third Normal Form (3NF)

Third Normal Form (3NF) is a normalization level that ensures that a table is not only free from partial and transitive dependencies but also that all its attributes are directly dependent on the primary key. The video script provides an example of how to identify and eliminate transitive dependencies to achieve 3NF.

💡Atomic Value

An atomic value is a data element that cannot be further divided into smaller pieces. In the context of normalization, ensuring that each table cell contains an atomic value is part of achieving 1NF. The video script uses this term to contrast with non-atomic values, which would violate the principles of 1NF.

💡Anomalies

Anomalies in database normalization refer to issues that arise due to poor data organization, such as update, insert, or delete problems. The video script discusses how normalization aims to eliminate anomalies by structuring data in a way that each piece of information is stored only once and is easily accessible.

💡Consistency

Consistency in the context of the video refers to the uniformity and reliability of data across a database. Achieving normalization helps maintain consistency by ensuring that there are no duplicate data entries and that data dependencies are logically structured.

💡Boy Scout Normal Form (BCNF)

The Boy Scout Normal Form (BCNF) is a stricter version of 3NF that requires every determinant to be a candidate key. The video script mentions BCNF as part of the higher levels of normalization beyond the scope of the discussed 1NF to 3NF, indicating a further step in the process of refining database structure.

Highlights

Normalization is a process used to organize attributes or columns in a table to ensure a well-structured database with minimal duplicate data.

An ideally structured table contains data with minimal duplication, aiming for no duplication if possible.

The importance of tables being free from anomalies and having consistent data is emphasized.

Understanding dependencies or functional dependencies is crucial for the normalization process.

The concept of partial dependency and its role in the second normal form (2NF) is introduced.

Transitive dependency and its impact on the third normal form (3NF) are explained.

The process of checking if a table is in the first normal form (1NF) involves ensuring each cell contains a single value.

To achieve 2NF, remove partial dependencies by identifying primary keys and their related partial dependencies.

An example of breaking down a table into multiple tables to eliminate partial dependencies is provided.

The process of eliminating transitive dependencies to achieve 3NF is discussed.

An example is given to illustrate how to split a table to remove transitive dependencies and anomalies.

The final result of normalization includes multiple tables with minimized dependencies and anomalies.

The video promises to cover more detailed examples and case studies in upcoming videos.

The significance of understanding different types of dependencies for successful normalization is reiterated.

The video concludes with a reminder to watch the next videos for further study cases on normalization.

The presenter wishes the viewers a good day and hopes they gain new understanding from the video.