Getting Started with UML Learning 3 object-oriented modeling

1. Why to use UML modeling

What is the model? The model is the abstract simulation and simplification of the shape or state of the real world, which provides the skeleton and blueprint of the system.

Models help visualize the system in terms of the actual situation or the desired style.

The model can regulate the structure or behavior of the system.

The model provides a template to guide the construction of the system.

For the system users, the software development model describes the software developers ' understanding of the software system requirements. Let the system user view the Software object model and find the problem, so that the developer is not going to be wrong from the start.

For software development, the object model of the software helps them to communicate the requirements of the software and the architecture and functions of the system.

For software maintenance and technical supporters, the software's object model can help them understand the architecture and functions of the program and quickly fix the problems that arise in the software after the software system has been running for a long time.

Modeling is not only for large software systems, but even a small message book can benefit from the modeling process.

2. The development model based on object-oriented modeling

The software lifecycle can be divided into planning, requirements analysis, design, coding, testing, operation and maintenance. The software development model is a framework of all internal radiant structures implemented by system development, operation and maintenance across the entire software lifecycle, The relationship between each stage of the software development activity is given. Here are 4 common development patterns.

(1) Waterfall model

The waterfall model is also soft for the life cycle model, its core idea is to simplify the problem according to the corresponding procedure, to separate the system function and the system design work, to facilitate the division of labor between the project and the coordination parts, That is, the logical implementation is separated from the physical implementation by the structured analysis and design method. The waterfall model divides the software lifecycle into 6 stages of project planning, requirement analysis, software design, software implementation, software testing, software operation and maintenance. and set their top-down order, each phase is sequentially connected.

The waterfall model provides a phased checkpoint for the project, this is beneficial to the organization and management of the personnel in the process of software development. The waterfall model does not focus on the following stages until the current phase is complete, which helps to develop large projects. Then there are some flaws. For example, when development results have not been tested, Users can not see the software effect, can not be in the development process of timely feedback, increase the risk of the project development process. There is a lack of flexibility for projects that require instability. It is also difficult to fully identify all the requirements of the system user in the requirements analysis phase.