Software Development Life Cycle

Software Development Life Cycle (SDLC):

The methodology of improving the software quality at the development process. We have multiple SDLC models.

SDLC phases:

• Requirements gathering
• Analysis
• Designing
• Coding
• Testing
• Implementation
• Support

SDLC Models:

Waterfall model(Sequential Process): When the project is small and the user requirements are constant, the organization is going to implement the waterfall model. Here is the place to implement all the 5 stages which we have seen in a Sequential manner or Sequential process.
Phases of Waterfall Models:

• Analysis
   i/p ↓ o/p
  
• Design  
   i/p ↓ o/p
• Coding  
   i/p ↓ o/p
• Testing  
   i/p ↓ o/p
• Maintenance

Prototype model(Review Facility): When the project size is small, the user requirements are variable then the organization is going to choose this model.

Theme: The user can have the review facility in the analysis stage only.

Iterative model or Incremental Model (Version model): When the project size is large, user requirements are variable then the organization is going to choose this model.

Theme: A place to complete the entire project with respect to modules or versions.

Analysis → Design → Code → Test             Increment - 1

                                                                                ↓ 

    Analysis → Design → Code → Test            Increment - 2         

                                                                                    ↓

        Analysis → Design → Code → Test             Increment - 3 

Fish model: When the project size is large and user requirements are variable then the organization is going to choose this model.

Theme: The user can have the review facility at the end of every stage.

Verification -Validation model: Verification belongs to the developer end. Developers can concentrate on their process which is implementary to develop the project.

Validation belongs to testing and Test engineer can concentrate on a product as it is right product or wrong product.

Theme: We can implement both development and testing activities simultaneously. So, it is an excellent model among all models.

Spiral model: In the spiral model, we have a PDCA life cycle that exists in each and every stage of SDLC.

Agile model: It refers to a software development approach based on Iterative development process. Each iteration is going to involve a team working through the SDLC process before giving a demo to the client.