UML Component Diagram: Everything You Need To Know

Learn what a diagram is and how it can be used to model relationships between processes. This guide covers the basics of component drawing, including different component drawing concepts, why they are used, and a few use case diagrams.

uml component diagram
In this article
  1. What is a Component Diagram?
  2. Component Diagram Symbols and Notation
  3. When to Use the Component Diagram
  4. How to Draw a Component Diagram?
  5. Component Diagram Examples
  6. Conclusion

It is not easy to comprehend the inner workings of complicated systems in the complex fields of software engineering and system design. Component diagrams are an extremely useful tool in this situation. Component diagrams are helpful aids for novices entering the field of system design and software development.

A component diagram makes navigating complex systems easier, much like a map. It presents a clear view of a system's architecture by breaking down its constituent parts visually and demonstrating how they work together. With straightforward explanations of their importance and application, this beginner's guide will help you understand the complexities of component diagrams. This article can help anyone, whether they are a student, an aspiring software developer, or just a naturally curious person, grasp the potential of component diagrams.

Part 1. What is a Component Diagram?

To make complex object-oriented systems easier to handle, component diagrams are used to divide them into smaller components. It simulates how a system would appear physically inside a node, including files, executables, libraries, etc.  It helps visualise the relationships and configurations between components that exist in your system. This helps create a workable system. 

A component diagram, also known as a UML component diagram, describes the organisation and connections of the physical components of a system. Component diagrams are often drawn to support model implementation details and double-check that all aspects of the functionality required for the system are included in the planned development.

Components are separate units of a system that can be replaced and run. The implementation details of a component are hidden, and an interface is required to execute its functionality. It is like a black box whose behaviour is described by the interfaces provided and required. Component diagrams are used to visualise the organisation and relationships between components in a system. These diagrams are also used to create executable systems.

The main purpose of the component diagram is as follows:

  • It foresees every part of the system.
  • Creates executable files by combining forward and reverse engineering.
  • It describes the relationship and cooperation between things.

Part 2. Component Diagram Symbols and Notation

The following are the types of shapes you commonly encounter when reading and drawing component diagrams.

Component Diagram Symbols

An object that is needed to perform a stereotypical function. Components provide and help understand the behaviour through interfaces as well as other components.


Node Symbol

Node symbol represents a hardware or software object at a higher level than its component.


Interface Symbol

Interfaces can be displayed as text notes or symbols, such as lollipops, rosettes, or balls.


Port Symbol

A port symbol represents a single point of interaction between a component and its environment.


Package Symbol

It groups several system elements together and appears as a file folder in Edraw.


Note Symbol

Developers can attach meta-analysis to component diagrams using note symbols.


Dependency Symbol

It shows that one part of the system is dependent on another part.


Component Diagram Notation

The UML notation is a notation designed for application object modelling, and in particular, it continues and expands the notations of the OMT (Object Modeling Techniques) method and the Booch method. More precisely, it describes the principles of organising use cases, classes, objects, and sequence diagrams.


In UML diagrams, components are represented as rectangles with additional compartments arranged vertically. It may contain the component name and boilerplate text and/or a component icon.                                      



In a UML model, a node is a model element that represents a system's computing resources, such as a personal computer, sensor, printing device, or server. Nodes can be connected by communication paths to describe the network structure.                                        

Fig node-name

Part 3. When to Use the Component Diagram?

Usually, component diagrams are employed throughout the project's planning and design phases. They aid in the visualisation of a system's structure and interrelationships. The following situations call for the use of component diagrams:

  • Project Planning: Component diagrams are helpful for project planning. They assist you in selecting how to arrange and construct the components by enabling you to disassemble a complex system into smaller, more manageable pieces.
  • System Design: Component diagrams can be used to define and show the structure of your program or system during the system design process. This aids in determining how parts will work together and transfer data or information.
  • Communication: When you need to describe your project to team members, stakeholders, or clients, component diagrams can also be employed. They make communication easier by offering an unambiguous visual depiction of the architecture of the system.
  • Maintenance and Documentation: For continuing system maintenance and documentation, component diagrams are helpful. They act as a point of reference for comprehending the architecture of the system, which facilitates upgrades and problem-solving.

Part 4. How to Draw a Component Diagram?

Component diagrams are useful for representing the physical aspects of a system, including files, executables, and libraries. The main purpose of a component diagram is different from that of other diagrams. It is used during the implementation phase of all applications. We design the system using a variety of UML diagrams, and once the artefacts are ready, we use component diagrams to provide insight into the implementation. This plays an important role in efficiently implementing applications.

Before creating a component diagram, it is necessary to identify the following artefacts:

  • What files does the system use?
  • How are the pertinent artefacts and libraries being applied?
  • What connection does each item have to the others?

After the artefacts are located, the following considerations should be made:

  • Identifying the component for which the diagram is about to be constructed by giving it a meaningful name.
  • It is necessary to create a conceptual blueprint before making the necessary tools.
  • Notes can be used to help explain the key points.

Part 5. Component Diagram Examples

Here are three use case diagrams that signify the role component diagrams play in helping us understand the project easily.

Online Store Process UML Component Diagram

The UML component diagram for online store process illustrates software components and their interactions within an online retail system. Let's explore the essential components and their functions in this diagram.


  • Search Engine: Enables users to search for products.
  • Inventory: Manages the product database.
  • Shopping Cart: Allows customers to add and review items.
  • Orders: Handles payment and order fulfilment.

How They Work Together:

  • Users utilize the Search Engine to find products they wish to purchase.
  • The Inventory component ensures that product information is up-to-date and accurate.
  • Customers add selected items to their Shopping Cart for a seamless shopping experience.
  • The Orders component takes care of the order process, from payment to delivery, ensuring a smooth transaction.

Component diagram for Student Administration

A UML Component Diagram for Student Admin is a visual aid for developing, updating, or enhancing student administration systems. It illustrates software components and their interactions. Let's explore the main components in this diagram.


  • Student User Interface: Student interaction, including course registration and grade checks.
  • Administrator User Interface: Administrative tasks, managing records, and student communication.
  • Communication Module: Facilitating communication between students and administrators.
  • Credentials Management: Ensuring secure access to the system.
  • Data Storage: Managing student records and information.

How They Work Together:

  • Students interact with the system through the Student User Interface to perform tasks such as course registration and grade checking.
  • Administrators access the system via the Administrator User Interface to manage student records, address queries, and communicate with students.
  • The Communication Module enables seamless communication between students and administrators, facilitating the exchange of messages and notifications.
  • Credentials Management ensures secure and controlled access to the system, safeguarding sensitive student information.
  • Data Storage stores and manages all relevant data, making it accessible for both students and administrators.

Component diagram for ride-sharing App

Ride-sharing apps have become a popular way to travel conveniently and efficiently. Let's explore the essential components of a ride-sharing system represented in the diagram.


  • Rider: The person requesting a ride.
  • Driver: The one offering transportation services.
  • Administrator: Manages user accounts and monitors activities.
  • Payment Processor: Enables secure transactions.
  • GPS System: Provides real-time route tracking.

How It All Works Together:

The ride-sharing app's components work in harmony to provide a safe and efficient transportation experience. Here's how it all comes together:

  • A rider uses the app to request a ride from their current location to their destination.
  • The driver receives the ride request and uses the GPS system to navigate to the rider's location.
  • The administrator oversees user accounts and ensures a secure and trustworthy environment.
  • After reaching the destination, the rider can conveniently make the payment through the integrated payment processor.

Part 6. Conclusion

A component diagram is a fundamental diagram that engineers often create in the early stages of a project. However, the usefulness of a component diagram spans the entire life of the system. Component diagrams are vital because they model and document the system architecture.

Since the component diagrams document the system architecture, the system's developers and future system administrators find this work important for understanding the system. Learning how to draw a component diagram is an essential skill a professional in the concerned field must have. EdrawMax is a very useful tool for designing and creating component diagrams for professionals.

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Edraw Team
Edraw Team Jul 04, 24
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