SE 23: Coupling & Cohesion with Examples | Software Engineering

CS & IT Tutorials by Vrushali 👩‍🎓

15 Mar 202313:45

Summary

TLDRThe transcript discusses software design concepts, focusing on the importance of cohesion and coupling in engineering. It explores various models like the teacher, student, and hood models, emphasizing their interdependencies and functions. The session delves into the significance of modularity, highlighting how it impacts software design and development. The speaker also touches on external coupling, control coupling, and the role of communication in software models. The discussion aims to provide insights into effective software design strategies that enhance maintainability, scalability, and reliability.

Takeaways

😀 The session focuses on the importance of software design, concepts, and engineering subject playlists.
🎓 It explores the next important topics, including session types, good and bad software, design coupling, and cohesion.
🔍 The discussion covers important questions that have been asked in previous sessions, emphasizing the need for understanding the relationship between software models.
🔗 It delves into the different types of models like teacher model, student model, hood model, and office model, and how they share information.
📊 The session explains the concept of dependency and the number of relationships between software models, using diagrams to illustrate total and four models.
🛠️ It introduces the idea of 'no dependency, no' in the second diagram, which is about model relationships and information sharing methods.
🔄 The concept of cardinality is discussed, which is about the degree of dependency and the number of relationships between software models.
💬 Communication between models is highlighted, emphasizing the need for models to work on input and output data, and the importance of updating records in databases.
🔢 The session also touches on the importance of logical cohesion, where elements of the model perform similar types of operations, such as error handling, sorting, searching, etc.
🔧 The benefits of high cohesion and low coupling in software design are discussed, including improved reliability, maintainability, and the ability to make changes with minimal impact on other models.

Q & A

What is coupling in the context of software design?
-Coupling refers to the degree of interdependence or the number of relationships between different software modules. High coupling means modules are highly dependent on each other, while low coupling means they are independent.
What are the different types of coupling?
-The types of coupling include no coupling, loose coupling, and strong coupling. No coupling means modules do not share any information, loose coupling means modules share minimal information, and strong coupling means modules heavily depend on each other.
What is cohesion in software design?
-Cohesion refers to how closely related the responsibilities of a module are. High cohesion means that the module's elements are highly related and perform similar tasks, while low cohesion indicates that the module performs unrelated tasks.
Why is low coupling and high cohesion preferred in software design?
-Low coupling and high cohesion are preferred because they improve readability, maintainability, and reusability of the software. Modules with low coupling and high cohesion are easier to understand, test, and modify without affecting other parts of the system.
Can you provide an example of global coupling?
-An example of global coupling is when multiple modules in a program share and depend on a global variable. For instance, in a school management system, a global variable like 'teacherCount' might be shared across different modules.
What is external coupling?
-External coupling occurs when two or more modules in a project depend on external tools, devices, or libraries. For example, if a module imports an external library for file handling or communication protocols, it is considered external coupling.
What is logical cohesion?
-Logical cohesion occurs when elements within a module perform similar types of operations but may not be related in terms of functionality. For example, error handling, sorting, and searching operations grouped in one module demonstrate logical cohesion.
What is procedural cohesion?
-Procedural cohesion refers to the elements of a module being related by the order in which tasks are performed. For instance, if a module contains functions that must be executed in a specific sequence, like reading data, processing it, and then saving it, this is procedural cohesion.
What is the difference between coincidental cohesion and functional cohesion?
-Coincidental cohesion occurs when the elements within a module have no meaningful relationship, whereas functional cohesion happens when all the elements of a module contribute to a single, well-defined task or functionality. Functional cohesion is highly desirable in software design.
Why is high cohesion important in software design?
-High cohesion is important because it ensures that the module's elements are related and work towards the same goal. This makes the system easier to maintain, understand, and test, and promotes code reuse.

Outlines

00:00

😀 Software Design Concepts

The first paragraph introduces the topic of software design, focusing on the importance of understanding various models and their relationships within the context of a project. It discusses the need for good software design practices and the benefits of high cohesion and low coupling in software models. The paragraph also touches on the types of models, such as teacher model, student model, hood model, and office model, and how they share information with each other. It emphasizes the significance of defining the degree of dependency and the number of relationships between software models. The discussion also includes the importance of diagrams for visualizing the total model and the functions within it, as well as the methods used to handle dependencies and data flow between models.

05:01

😀 Cohesion and Coupling in Software Design

The second paragraph delves deeper into the concepts of cohesion and coupling in software design. It explains how cohesion refers to the degree to which the elements within a module belong together, while coupling refers to the degree of interdependence between modules. The paragraph highlights the importance of designing software with high cohesion and low coupling to achieve a robust and maintainable system. It also discusses different types of cohesion, such as coincidental, logical, and functional cohesion, and their impact on software design. The paragraph further explores the concept of logical cohesion and how it allows for similar types of operations to be performed on the elements of a model. Examples are given to illustrate how different elements can perform similar operations, and the importance of understanding these relationships for effective software design is emphasized.

10:10

😀 Understanding High Cohesion and Low Coupling

The third paragraph emphasizes the importance of high cohesion and low coupling in software design. It discusses how high cohesion within a module allows for better understanding and maintenance, while low coupling between modules enables easier changes with minimal impact on other parts of the system. The paragraph also explains the benefits of these design principles, such as improved reliability, maintainability, and testability of the software. It further elaborates on how to achieve high cohesion and low coupling by understanding the relationships between data and how to design models that can be easily tested and modified. The paragraph concludes by stressing the importance of these concepts in creating a well-designed software system that is both efficient and effective.

Mindmap

Keywords

💡Software Design

Software Design refers to the process of defining the architecture, components, interfaces, and other aspects which make up a software system or application. In the context of the video, software design is central to the discussion as it involves creating effective and efficient systems. The script mentions 'Session Start' and 'Software Design Cappling and Cohesion', indicating that the video is focused on how to structure software in a way that enhances its functionality and maintainability.

💡Cohesion

Cohesion in software engineering is a measure of how closely related the functions performed by a module are. High cohesion indicates that a module has a clear purpose and responsibility, which is desirable for creating maintainable and understandable code. The video script discusses 'Design Cappling and Cohesion', emphasizing the importance of cohesion in ensuring that software components are well-integrated and perform a single, well-defined function.

💡Coupling

Coupling refers to the degree of interdependence between software modules. In the script, 'Dependency No In' and 'Dependency No Out' diagrams are mentioned, which are likely used to illustrate different types of coupling and their impact on system design. The video seems to advocate for low coupling to ensure that changes in one module have minimal impact on others, promoting flexibility and ease of maintenance.

💡Model

A model in software engineering is a simplified representation of a system or process used for understanding, analyzing, or designing an aspect of a system. The script mentions various types of models like 'Teacher Model', 'Student Model', and 'Hood Model', which are probably used to represent different aspects of the software system being discussed. These models help in visualizing and organizing complex information, aiding in the design and development process.

💡Global Variables

Global variables are variables that are defined in one module and can be accessed by other modules. The script touches upon 'Global Variables Right' and 'Example Global in Teacher', indicating a discussion about the use of global variables in software design. While they can be convenient, they can also lead to issues with maintainability and testing if not managed properly.

💡External Coupling

External coupling refers to the dependencies a software module has on external tools, libraries, or devices. The video script mentions 'External Coupling' in the context of accessing more models in one project, suggesting the use of external tools and libraries. This type of coupling is important to discuss as it can impact the portability and flexibility of the software system.

💡Control Coupling

Control coupling is a type of coupling where one module controls the sequencing of another. The script refers to 'Control Comply Generally Handles Functional Flow Bit', which might relate to how modules are orchestrated and controlled within the software system. Understanding control coupling is crucial for designing systems that are predictable and manageable.

💡Data Coupling

Data coupling is a form of coupling where modules are connected through the exchange of data. The video script mentions 'Data Coupling See Here Kind of Functionality', indicating a focus on how data is passed between modules and its impact on the system's design. Data coupling is a key aspect of software design as it influences the system's modularity and the complexity of inter-module communication.

💡Class of Model

A class of model refers to a category or type of model that serves a specific purpose within software design. The script talks about 'Class of Model Execution Information', which could be discussing how different classes of models are used to represent and manage different types of data or functionality within the software. This concept is important for understanding how models are organized and utilized in the design process.

💡Consistency

Consistency in software design refers to the uniformity and predictability of the system's behavior and structure. The video script mentions 'Consistency Coupling', which likely relates to the need for consistent behavior across different parts of the system. Ensuring consistency is vital for creating software that is reliable and easy to understand, as it helps prevent errors and makes the system more intuitive for users and developers.

💡Logical Cohesion

Logical cohesion is a measure of how logically related the functions within a module are. The script discusses 'Logical Cohesion Misses', which could be referring to the importance of ensuring that all functions within a module are logically connected and serve a common purpose. Logical cohesion is a key aspect of creating modular, maintainable, and understandable software systems.

Highlights

Introduction to the session on software design, concepts, and engineering subject playlists link.

Discussion on the next important topics, including session starting, types, and good and bad software.

Exploration of important questions that have been asked in previous sessions.

Explanation of the concept of coupling and cohesion in software design.

Different models like teacher model, student model, hood model, and office model are introduced.

Sharing of information with each other through these models is discussed.

Definition of coupling in terms of degree of interdependence and number of relationships between software modules.

Discussion on the four types of models and their sharing of information functions.

Explanation of how to handle no dependency and no in-degree in the second diagram.

Introduction to the concept of cordless coupling and its benefits.

Discussion on how to reward loop coupling like in the diagram.

Explanation of the global variables and their impact on the model.

Introduction to external coupling and its types in a project.

Explanation of control coupling and its general handling of functional, flag, and boolean-related information.

Discussion on data coupling and its importance in passing information between modules.

Introduction to class of model execution information and its methods.

Explanation of how to generate good design by understanding high cohesion.

Discussion on the importance of logical cohesion and how elements of the model perform similar types of operations.

Introduction to procedural cohesion and its role in executing functions within the program.

Explanation of communication cohesion and how it works with input and output data.

Discussion on sequence cohesion and how it deals with the output of one element to the next input element.

Introduction to functional cohesion and its role in performing similar types of functionalities through different elements.

Discussion on the importance of understanding the relationship between data and how it leads to good design.

Explanation of how high cohesion and low coupling can lead to better software design.

Discussion on the benefits of high cohesion, such as maintainability and the ability to make changes with minimal impact.

Introduction to the concept of model development with an emphasis on accurate design.

Explanation of how high cohesion allows for easy removal of models with the least amount of coupling.

Discussion on the importance of testing ability and how high cohesion and low coupling make it easier to test models.

Conclusion on the importance of cohesion and coupling in software design and how they contribute to good design practices.