Software Development Life Cycle (SDLC) Overview – Process, Phases, And Models

SDLC implies Software Development Life Cycle. As its name suggests, the SDLC represents the complete set of methods required to develop any software product. Additionally, it also incorporates all software developer activities during the development process of any software product. 

What is SDLC?

Software Development Life Cycle (SDLC) is a process of developing software products with a very high and premium quality. The software development process requires to take into account the needs and requirements of customers. Before starting to develop any product, it is essential to plan first. The software development life cycle also includes the planning, selecting methods, and proper approaches for developing the software.

The development of software is categorized into different phases. Each phase is developed efficiently using an appropriate approach. Software developers and system engineers are responsible for producing high-quality software products within the given and estimated time and cost. Several methods of SDLC are created for software development. 

SDLC

Why Choose SDLC?

Software Development Life Cycle process for developing every software product is essential. Also, there are specific reasons why developers use this approach. The following are some significant reasons to choose SDLC:

  1. SDLC acts as a map for developers. It incorporates all planning, scheduling, development strategies, and everything required to produce good-quality software.
  2. As SDLC is performed in phases, developers can focus on every stage to generate a premium-quality product. 
  3. Customers are provided with a provision of focusing on every phase of the software during its development process. 

Need For SDLC

For every software product to develop, it must first have systematic and proper planning. Planning is the first and the foundation phase of any work that we perform. The SDLC involves planning, building design, testing, and installation. 

If any work is divided into small parts, it becomes effortless to execute each piece very accurately and correctly. The same is the idea used in SDLC. The entire development process is divided into seven stages. Dividing the development process into small chunks makes it easier for the software development team members to effectively and efficiently carry out each phase.

Phases of SDLC:

The activity of the software development life cycle is categorized into seven different phases. These SDLC phases are Requirements collection and analysis, Feasibility and study, Design, Coding, Testing, Installation or Deployment, Maintenance. Let us have a thorough glance at each of these six phases.

Software Development Life Cycle (SDLC)

1. Requirements Analysis

The very first stage of the SDLC is the requirements collection and analysis. The owner of the software product has his or her wishes about the product. The software development team needs to collect the requirements and demands of the customers and stakeholders. These needs can be how the software should have its appearance, what functionalities it should possess, who can use it, and many others. 

If the development team is acquainted with these stakeholders’ requirements, it becomes easier for them to plan every phase. This phase of SDLC plays a very crucial role, as it is the foundation stage. So, having a clear understanding of the needs and demands of customers is essential. 

2. Feasibility Study

Another stage of the SDLC is the feasibility study. Once the development team gathers all the software product requirements, they need to draft all these requirements in one document. This document is usually referred to as the Software Requirements Specifications. The acronym for it is ‘SRS.’ This document plays a very role in the whole development process as it incorporates all specifications specified by the customers. 

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3. Design

Designing the software is the third stage of the software development life cycle. The development team needs to draft the entire architecture of the software system. Generally, the software system’s design is categorized into high-level design and low-level design. For every software development, these two kinds of design documents are necessary and essential. 

The high-level design (HLD) document incorporates information as follows:

  • The name of the modules included in the software and their brief explanation.  
  • Next, the functionality of each module is also described. 
  • HLD also encompasses the relations between the modules. 
  • All the database tables involved in the software product are mentioned along with their essential elements. 
  • Lastly, it contains the architecture of the software system. 

The Low-Level Design (LLD) document has the following information:

  • Functional logic of each module present in the software product
  • The size as well as the type of the database tables
  • It includes detailed information about the interface of the software. 
  • Error messages are also listed in the LLD
  • Information about the input and output to every module of the software product is included. 

4. Coding

The next after the designing stage of the software development life cycle is the coding. Coding is the core of any software system. All the functionalities of the software product are developed through coding. Several programming languages are available for the development of the product. So, the development team has to choose the programming language. 

However, this phase of the software development is considered as the most extended phase. This stage is again divided into four sub-phases, and every team member is assigned to one of these four sub-phases. After developing the code, it is compiled and interpreted. So, tools, like compiler, interpreter, and debuggers, must verify the code’s correctness. 

5. Testing

After the coding phase is completed, it is essential to check whether it works properly, whether all functionalities go well, and many other factors. This phase is called testing. The software developers are not responsible for testing the software. There is a team of software testers. This stage of software development is specially meant for detecting defects and bugs in the software system. 

Also, the testers test whether the system functions appropriately according to the needs stated by the stakeholders. If they find defects or bugs, the system is then sent to the software developers. The development team focuses on the bugs and finds a solution to it. Once done, it is again sent to the testing team to verify. When no defects and bugs are found, the software product is eligible to undergo the SDLC’s next phase. 

6. Installation or Deployment

Once the software system is free from defects and bugs, it is sent to the project manager for feedback. If the project manager states any changes as feedback, the system needs to change. It is again sent to the developers and then testers. If the feedback does not have any changes, the software system is ready to install. It is released in the market, and customers start using it. 

7. Maintenance

After the software system is released into the market and used by the customers, there may be three significant issues, bug fixes, upgradation, and enhancement. When customers start using a particular software product, they may face problems or report bugs in it. So, these issues need to be resolved. 

Upgradation of the software implies developing newer versions of the software. So, in the more recent version, these reported bugs can be demolished. In this upgrade, developers can also enhance existing features or add new features to the software. This activity of adding and improving features is referred to as enhancement. 

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All these phases of the software development life cycle ensure that the software product meets all the customers’ requirements and needs. Along with these phases, the communication between all the members involved in the entire development process is very significant.

SDLC Models

The software development life cycle (SDLC) is available in several models. Some of these commonly-used and highly preferred models are:

  • Waterfall Model
  • Incremental Model
  • Agile Approach
  • V-Model
  • Spiral Model
  • Big Bang Model
SDLC Models

Let us look at a glance at each of these models. 

1. Waterfall Model

The waterfall model is one of the most popular and oldest SDLC models. This model of SDLC was the first to develop. However, it is straightforward and easy. This model’s principal idea is that the software system’s current phase should complete before starting the next step. This is because the out of the first phase is taken as the input to the next stage. 

The waterfall model is the sequential model because the complete process is executed sequentially, i.e., the phase is executed only if its previous step gets accomplished. So, it is also called Linear-Sequential Life Cycle Model. One of the most excellent perks of using this model is that it is elementary to understand and does not overlap the development phases. It is best suited for the development of small projects. 

But, if there are any changes mentioned by the customers at the testing phase, it is complicated to go to the previous degrees and change them. So, this model should be chosen only if the requirements are complete and precise. 

2. Incremental Model

Another popular model of SDLC is the incremental model. In this type of model, the requirements and needs are broken down into multiple parts. Each part of the conditions has to undergo analysis, designing, coding, and testing stages. This model enables software developers to execute multiple requirements parallelly. Also, the highest priority requirement can be performed first. 

Using this model, software developers can develop each requirement very carefully. The incremental model is best suited for lengthy projects. But. Developers must have a clear understanding of the needs as they are divided into multiple modules. Additionally, the software is developed very quickly using this approach. But the cost of implementing this model is prohibitive.

3. Agile Approach

The Agile approach is one of SDLC’s highly-used models in today’s world for developing software products. In this approach, the tasks required in the development process of the software are broken down into several iterations. But, developers need to define the necessary time to develop each iteration and the cost in advance. Dividing the entire project into smaller tasks results in decreased risk. Also, the delivery of the software product becomes quicker and faster. 

As the entire development process is categorized into multiple iterations, each iteration must go through all SDLC phases. In the testing phase of the agile approach, various advanced methods are used. These methods are scrum, crystal, dynamic software development method, feature-driven development, lean software development, and eXtreme Programming. 

The great advantage of using the agile approach is the faster delivery of the product. Another most significant benefit of using this SDLC model is that it accepts changes in requirements in any development phase. 

4. V-Model

V-model is yet another popular SDLC model, which involves executing the software processes in a V-shape. Also, ‘V’ in the context of the V-model implies the Verification and Validation model. V-model is the advanced version of the waterfall model. In the V-model of the SDLC, each phase is associated with the testing phase. This has become easier for testers to detect bugs and defects at every stage of the development. 

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The verification and the validation phases in the V-model are carried out in the V-shape. The verification phase analyzes without executing the, while the validation phase involves analyzing and testing after the code is executed. In the validation phase of the V-model, there are four distinct phases. These phases are as follows:

This model is highly suitable for small projects. As every phase is associated with the testing phase, the bugs do not flow down the current stage. 

5. Spiral Model

The spiral model is formed by combining iterative and waterfall models. It involves our phases, and the software product has to undergo every stage in an iteration. This iteration is called a spiral. The grades in the spiral model are listed below:

  • Identification
  • Design
  • Construct
  • Evaluation and Risk Analysis

The benefit of using this model is customers can change their requirements in any phase. Also, customers are allowed to see the software in the very early stages. It is best suited for the large-sized software projects that have higher risks. 

6. Big Bang Model

Another model of SDLC is the Big Bang model. This model is straightforward to use and does not require any specific procedure. However, the development process also does not require detailed planning. The development of the software product is based on the available funds. Additionally, the requirements of the stakeholders are also not defined clearly. So, the outcome of the development is unpredictable. 

The advantage of this model is it does not require detailed planning of the development process. Also, the resources for development are needed for a minimal amount. But, the most significant disadvantage is there are higher chances of risks and uncertainty, which is not affordable. This model should be used only if the requirements are adequately defined. 

Pros and Cons of Software Development Life Cycle

Pros:

  1. The software development life cycle is best suited for handling and monitoring projects very efficiently and effectively
  2. It involves detailed steps in the development of each phase of the software product
  3. This process has the proper and well-organized documentation of the requirements and demands of customers
  4. After developing each phase, the formal review is produced that enables developers to manage the software efficiently

Cons:

  1. The waterfall model of the SDLC is very inflexible
  2. As the SDLC process requires detailed documentation of the requirements, i.e., System Requirements Specification, it takes a long time and requires higher costs
  3. The SDLC process requires well-organized and detailed planning of the entire development process
  4. Customers are not involved regularly in the development process

Conclusion

The SDLC is a well-organized and proper-planned process for the development of any software product. All phases involved in the SDLC process ensure the generation of good and premium quality products. Later, we have seen detailed actions performed in each step of the SDLC. We covered six distinct and popular models of SDLC. Lastly, we have seen some advantages and disadvantages of the SDLC process. 

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