Common software development models include waterfall model, evolution model, spiral model, and fountain model .
1. Waterfall Model ( Waterfall Model ):
The software life cycle is divided into basic activities such as requirement analysis, software design, program writing, software testing and operation and maintenance, and stipulates a fixed sequence of them from top to bottom, which is connected with each other, like a waterfall, falling down step by step.
Not adapting to changes in user needs, the development model is linear, and users can only see the development results at the end of the entire process. The waterfall model is not suitable for software products with uncertain requirements.
Disadvantage: The waterfall model lacks flexibility to clarify otherwise unclear activities through development activities. Therefore, this model is only used when user needs are more specific.
2. Evolutionary Model : Also known as rapid prototyping model.
It is to build a prototype system of software products through some rapid prototyping languages, which can quickly interact with users. Users can understand the software specifically through the prototype system, and discover the omissions of user needs through the prototype. At the same time, the user participation rate is relatively high. The waterfall model has increased a lot, making up for the shortcomings of the waterfall model. However, it may lead to poor system design, low efficiency and difficult maintenance.
The rapid prototyping method can overcome the shortcomings of the waterfall model and reduce the development risk caused by unclear software requirements, which has a significant effect.
3. Spiral Model :
Combining the waterfall model and the evolution model combines the advantages of the waterfall model and the evolution model, and adds risk analysis.
Suitable for in-house large-scale software development: the spiral model emphasizes risk analysis,
Including 4 aspects of activities: planning, risk analysis, implementation engineering, customer evaluation;
4. Water Fountain Model :
Mainly used to describe the object-oriented development process. The term fountain embodies the iterative and gapless nature of the object-oriented development process. That is to allow development activities to intersect and iteratively proceed.
The various stages of the software development process are iterative and uninterrupted. A part of the software is often repeated many times, with related objects adding asymptotic software components in each iteration.
Iteration: The development activities in the model often need to be repeated many times, and the software system is continuously improved during the iterative process.
No gaps: Refers to the absence of clear boundaries between development activities (eg, analysis, design, coding).
It is suitable for object-oriented software development, and the development efficiency is relatively high.
The disadvantage is that conventional project management methods do not apply.
5. V Model (V Model ): This model emphasizes how the testing process should be related to analysis, design, etc. processes.
6. Incremental Model :
The advantage is that software development can better adapt to changes, and customers can continuously see the software being developed, thereby reducing development risks.
A software product is designed and coded as a series of incremental components.
In this way, products that can complete some functions can be quickly submitted to users, and users can have more time to adapt to the new system.
Such a development model requires an open architecture and may result in poor software design and low efficiency .