Software design: Basics and methodology in software engineering
This article looks into what software design is and its significant methods in software engineering. It will help beginners with the basic understanding.
Quite often, software development projects run into design errors, causing extensive delays, and incurring huge costs. The most crucial errors often take place in the initial development phase. This highlights the need to undertake software design methodology more seriously at the start of development.
Thankfully, software engineering has highly evolved over the time. Today, there’s no such problem that a software developer cannot counter. A software developer creates a problem domain; compares it with application domains of different design methods; choose the right methodology for custom software development. It all goes right if software design goes well.
What is software design?
Software design is the most important step in software development. It decides how the whole development will take place, which tools and strategies will be used, what the deadlines are and how the product will be tested, delivered, integrated, and launched.
In short, it is a whole set of activities for a software development project from start to the end.
According to Pressman Software Lifecycle Model, a software development project undergoes three main phases: definition, development, and maintenance. Software design comes under the development phase, putting forward how the project will be executed.
Software design methodology
It is important to note there that software design is a skill; it requires a structure to offer the methodology for development. That’s where software design methodology or approaches come in.
Each software design approach comes with unique characteristics. It can be functional, behavioral, or structural, depending on the needs and objectives. Software methodology uses different diagrams and models to ensure the right sequence of activities.
Role and significance of software design methodology
Design methodology is crucial for large projects that involve an array of programming languages being coded by different software developers.
Using an effective methodology offers the right communication channels so that all the developers keep end goals and objectives into consideration. Also, it helps translates design into codes, reducing the chances of errors.
Components of software design methodology
One project can use more than one design methodologies. As it is a systematic procedure, it follows certain activities in a particular order. Losing the order can disrupt the entire design.
Usually, software design methodology consists of four basic components:
- A conceptual model for understanding the basic problem and application
- A set of procedure for systematic activities
- A series of risks and constraints to be avoided
- A solid evaluation criteria to analyze the performance
Major software design methods
Also known as software design approaches, the methods of software design are mainly classified into the following:
1. Level-oriented design
The level-oriented design follows two common strategies: Step-Wise refinement and Design by Composition.
Step-wise refinement is also known as the top-down process. It begins at the topmost level and has the following significant features:
- It undergoes functional decomposition to create small modules which are easier to analyze, design and code
- It is dependent on the decisions made in the defining stage of the development process
- Each module is further decomposed into more detailed and refined small modules, known as the atomic level of a module
- All the modules are divided among software developers as per their skills and expertise.
This approach requires extensive understanding of the problem to follow the right structure. This is not a very flexible approach but still allows developers to add features and functions as the design evolves. Using iterative process, software team is well in charge of the overall development.
Design by Composition strategy moves along with the actual development. It uses previous solutions to build the next solutions. It has following features:
- It follows a bottom-up approach instead of top-down
- Developers build the lowest level solutions first-hand and then move towards the end product
- It can include additional features or processes at each step
Some other approaches that can come under level-oriented design include outside-in model, inside-out model, and most-critical-component-first model.
2. Data flow-oriented design
Software development companies often use data flow-oriented design process when detailed information is available. It helps derive the design as per provided information so that clients end up with the desired custom software.
This method uses different techniques such as Data Flow Diagram (DFD), Structured Analysis and Design Technique (SADT), and Structured Design (SD), etc.
Each of these techniques comes with a unique process and tools and follows a unique structure. Custom software developers are well acquainted with such concepts.
3. Data structure-oriented design
The data structure-oriented design dedicates its focus upon the object, which is usually the available information. This structured information determines the efficiency of algorithms used for the process.
There can be different types of data such as alternative data, repetitive data, and hierarchal data. The data is represented using hierarchal diagrams. Software developers look into the characteristics of data structure, map the data into control hierarchy, refine it and come up with procedure of the software.
4. Object-oriented design
This approach works upon certain entities classified as objects. This involves identification of objects and classes. The object has a private data structure and so, developers choose the operations accordingly.
All objects include data, and the entire data is encapsulated for use and re-use.
This is a rather new method of software design and is still evolving. It focuses on data design, architecture, and procedural design.
Software design is a series of well-established steps. The steps vary according to the software design methodology adopted for a project. For smaller custom software development projects, custom software agencies usually employ generic models such as top-down or bottom-up approach.
For large and complex projects, however, developers use rather well-defined approaches. This ensures systematic operations. Choosing the right methodology is the responsibility of professionals. All you need to do is choose the right custom software development firm such as FortySeven Software Professionals. With their expert IT services, rest assured that your project is in capable hands.
Story by Hanna Shnaider. She is an expert in custom software development. Over the years, she has worked with different software companies, gathering a rich experience in modern technologies. Click here to view her profile.