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Table of contents
1.
Introduction
2.
What is Transitive Dependency?
3.
How to avoid dependency
4.
Third Normal Form by Removing Transitive Dependency
5.
Drawbacks of Transitive Dependency
6.
Why are Transitive Dependencies bad for Database Design?
7.
Frequently Asked Questions
7.1.
Why should we remove transitive dependency?
7.2.
What do you understand by third normal form (3NF) in database management systems?
7.3.
In which normal form is the transitive dependency not allowed?
7.4.
What is a transitive dependency in open source?
7.5.
What are the advantages of transitive dependency management?
8.
Conclusion
Last Updated: Mar 27, 2024
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Transitive Dependency in DBMS

Author Monika Yadav
1 upvote
Master Python: Predicting weather forecasts
Speaker
Ashwin Goyal
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Introduction

Functional dependency defines the values of one or more attributes and determines the values of another attribute. It plays an important role in database design. As they help to ensure data integrity and prevent inconsistencies in the data. 

Transitive dependency defines the value of one attribute in a table depending on another attribute, which in turn depends on a third attribute. Moving forward, we will learn about transitive dependency in detail with examples. 

Now without wasting time, let’s start with the article and learn about transitive dependency in DBMS.

Transitive dependency in DBMS

What is Transitive Dependency?

Transitive dependency defines the value of one attribute in a table depends on another attribute, which in turn depends on a third attribute. We will get to know this concept more clearly through an example. Let’s consider a table of student grades. In which rows represent name, course, grade, and ID. If the grade depends on the course and the course depends on the ID, then it is said there is a transitive dependency between the grade and the ID.

Let’s take an example for better understanding

 STUDENT TABLE

STUDENT ID STUDENT COURSE CITY
101 NINJA 1 DSA SHIMLA
102 NINJA 2 ML DELHI
103 NINJA 3 JAVA MUMBAI

As we see in the above table:

Course→Student: Here, the Course attribute determines the Student attribute. If we know the course, we can learn the student name.

Student→City: If we know the student name then we can determine City.

Course→City: If we know the course, we can determine the city via the Student column.

If we take a closer look into the functional dependencies discussed above, they are indeed forming a pattern

A→B and 

B→C; therefore, 

A→C.

Similarly,

A→Course, 

B→Student and 

C→City

To ensure Third Normal Form(3NF) in the Student table, this transitive dependency must be removed and this process of removing transitive dependency is called Normalization.

Also read, File System vs DBMS

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How to avoid dependency

Dependencies are unavoidable in software development. Software systems have many components that rely on each other to function correctly. There are many ways to minimize and manage dependencies in software projects:

  1. By using abstraction: Abstraction is used for hiding implementation parts behind an interface. It reduces the coupling between components. By using abstraction, we can reduce dependencies between components. After removing dependencies, the system will be more modular and flexible.
     
  2. By using dependency injection: It is a technique where dependencies are passed to a component at runtime instead of being hard-coded into the component, which makes switching out dependencies easily or modify the system.
     
  3. By using interfaces and APIs: If we define interfaces and APIs between components. We can reduce dependencies and make it easy to extend the system. Components can communicate through interfaces. It reduces the coupling between them and makes isolating and testing individual components easier.
     
  4. By using design patterns: They are reusable solutions to common issues in software design. Using design patterns can reduce dependencies between components and make the system more modular and extensible.
     
  5. By using modular design:  It breaks down a system into smaller and more manageable components. Modular design can reduce dependencies between components. Moreover, make it easier to modify and extend the system.

Third Normal Form by Removing Transitive Dependency

Let's consider the Student table with three attributes(Student ID, Student, City) and try to find and eliminate the Transitive dependency from this table.
STUDENT TABLE

STUDENT ID STUDENT CITY
101 NINJA 1 SHIMLA
102 NINJA 2 DELHI
103 NINJA 3 MUMBAI

The following Student table is not in 3NF. As it has the transitive dependency. Let's learn how?

Student ID→Student

Student→City

Here functional dependency also exist,

Student ID→City

Now let’s eliminate the Transitive dependency. For removing transitive dependency we have to split the Student table in such a manner that Student ID will no longer functionally depend on Student city.

Now Let's split the table and create two new tables. One for {Student ID, Student} and another table containing {Student, Student City}.

STUDENT TABLE    

STUDENT ID STUDENT
101 NINJA 1
102 NINJA 2
103 NINJA 3

STUDENT CITY TABLE

STUDENT CITY
NINJA 1 SHIMLA
NINJA 2 DELHI
NINJA 3 MUMBAI

Now this Student table and Author City table contains no Transitive dependency and the relation is now in 3NF.

Drawbacks of Transitive Dependency

Some of the drawbacks of transitive dependency are as follows.

  1. Transitive dependencies can create problems in database design and management. For example, they can create redundancy issue.
     
  2. They can lead to inconsistency, and other issues. We can avoid these kinds of problems by normalizing a database by breaking down tables into smaller, and more manageable units. 
     
  3. They may reduce the performance and make database inefficient. Removing transitive dependencies by segregating the attributes into different tables can improve the database's performance and make it efficient.

Why are Transitive Dependencies bad for Database Design?

In database design, transitive dependencies occur whenever a table consists of a non-key attribute which is dependent on another non-key attribute in the same table, which itself is dependent on a key attribute. The non-key attribute is indirectly dependent on the key attribute, through the intermediary non-key attribute. The transitive dependencies can be bad for database design as follows.

  1. Transitive dependencies can create an issue in database design by violating the principle of database normalization. Database normalization is a process by which we can organize a database to minimize redundancy and avoid data anomalies, including update anomalies, insertion anomalies, and deletion anomalies. 

    If, in a database, transitive dependencies exist, it can lead to data anomalies, which can cause inconsistencies and errors in the data. 

    For better understanding, let’s take an example: Let’s say In a table, a non-key attribute is dependent on another non-key attribute and which too depends on a key attribute. If we update the key attribute it may result in inconsistencies in the data. 
     
  2. Moreover, transitive dependencies make it challenging to maintain the database. By increasing the complexity and cost of database management. In database design, To avoid transitive dependencies it is essential to follow database normalization principles and make sure that every table is designed to store only one type of data. 

    All non-key attributes in the table are dependent only on the key attribute which helps to ensure data integrity and data consistency. It makes it easier to manage and modify the database over time.

Also read anomalies in database and Entity in DBMS

Frequently Asked Questions

Why should we remove transitive dependency?

Removing transitive dependencies from a project can have many benefits like it reduces risks, provides stability. It also have faster build times and simplified maintenance.

What do you understand by third normal form (3NF) in database management systems?

Third normal form (3NF) is a level of data normalization. It ensures that each non-key attribute of a table is dependent on another non-key attribute, but not on a non-key attribute that is itself dependent on the primary key.

In which normal form is the transitive dependency not allowed?

In the Third Normal Form (3NF), transitive dependencies are not allowed. Transitive dependency occurs when a non-key attribute in a relation is functionally dependent on another non-key attribute instead of the primary key of the relation. We must decompose the relation into more minor relations to remove transitive dependencies. 
In 3NF, every non-key attribute is dependent only on the primary key and not on any other non-key attributes in the relation.

What is a transitive dependency in open source?

In the context of open-source software development and project dependencies, a "transitive dependency" refers to a situation where a project or software package depends on another project indirectly, through a direct dependency. 

What are the advantages of transitive dependency management?

Transitive dependency management is the process of managing dependencies in a software project. Some advantages of transitive dependency management are Easy maintenance, Better security, Efficiency development and also improvement in stability.

Transitive dependency management helps to ensure our software project is more stable, secure, and easier to maintain. Results in a more efficient development process and a better end product.

Conclusion

So far, we have discussed a lot about Transitive Dependency in DBMS. By this, we came to the end of the blog. We hope this blog adds knowledge to you and you get to know the basics of Transitive dependency. In conclusion, transitive dependencies can cause issues in database management systems, creating redundancy, inconsistency, and other issues. 

Issues can be removed by normalising the Database by breaking down tables into smaller ones and removing transitive dependencies by breaking up the attributes into different tables, which improve the efficiency, performance, and reliability of the database system. 

Overall, a well-designed and normalized database with minimized dependencies can provide a solid foundation for a reliable and efficient database management system. Must read 3NF-Third Normal Form

You can also consider our Database Management Course to give your career an edge over others.
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