"Requirements Engineering-software modeling and Analysis" reading notes 2

As the study progresses, my reading continues, and after reading the first and second parts of requirements engineering-software modeling and analysis-in the first phase, I read the third part of the book's needs analysis in the last few days, which is part of the focus of the book, and is also the most helpful in this part of my reading.

"Requirements Engineering-software modeling and analysis" in the requirements of this part of the analysis of requirements analysis, process modeling, data modeling, object-oriented modeling and other knowledge, in the reading I have a brief understanding of these knowledge, in the reading of my help is very big, understand in software engineering, Demand analysis refers to all the work that is required to describe the purpose, scope, definition, and functionality of a new system when building a new or changing existing computer system. Demand analysis is a key process in software engineering. In this process, the system analyst and software engineer determine the needs of the customer. Only after these needs have been identified can they be able to analyze and seek solutions to the new system. The task of the requirements analysis phase is to determine the functionality of the software system. Software requirements analysis is to study the user needs to get things, fully understand the user's software requirements of the complete function, to confirm the user software functional requirements, establish a verifiable, verifiable a basic basis. Software Requirement analysis is the beginning of a project and the most important key point of project implementation. According to the analysis results of the relevant agencies, we have designed the software products are not integrity, the correctness of the problem of more than 80% is the result of demand analysis errors, and due to demand analysis errors caused by the fundamental functional problems are particularly prominent. Therefore, a successful software requirements analysis of a project is a critical step. In order to ensure the normal implementation of the project, and can be successfully completed, we must strengthen the project management and focus on the project analysis work. We only from the actual start, the real grasp of user needs, grasp the user needs goals, grasp the user's future function definition, to ensure that our development work correctness direction. Three methods of demand analysis: Structural analysis method, object-oriented analysis method, problem-oriented analysis method. The structural analysis method is the traditional analytic method, its advantage is that can not need to define the system precisely in the demand stage, only need to determine the system function scope according to the business framework, as well as each function's processing logic and the business rule, the function requirement specification, the object-oriented analysis method's biggest benefit is in the demand stage, It is possible to describe a system very precisely, in a programming language, with end-user communication (the end user must be familiar with the language), to be able to identify many problems at the outset of the project, to avoid the need to iterate during the development process, and to eliminate the need for end-user involvement in the system design and development phases. This knowledge, as outlined in the Requirements Analysis section, is the basis for future modeling and is a great help for future learning.

In the back of the study is mainly about the modeling process, mainly the process modeling, data modeling, object-oriented modeling, each modeling method has its own characteristics, process modeling is a structural analysis method of the typical technology. Process modeling looks at the system as a collection of processes, some of which are executed, and others that are implemented by software systems. Process execution is the processing of data, he received data input, data conversion, output data results. The streaming diagram is the main modeling technique used in process modeling. There are four basic model elements that he needs when modeling: external entities, processes, data streams, and data storage. Data modeling takes the production and use of data in the system as the key point, takes the process of data transformation as the core, establishes the hierarchical process model to describe the system, and describes the behavior and data of the system. The abstract organization of data in the real world, determine the scope of the database to be governed, the organization of the data and so on into a real database. Three common data models: the conceptual data model, the physical data model, and the logical data model. Data modeling is the most commonly used method when the entity contact graph. The data modeling technique can compensate for the shortcomings of the process modeling in the data description, he describes the definition of data, structure and relationship characteristics. Object-Oriented modeling is the application of object-oriented methodology in requirement analysis, so it is also called object-oriented analysis. It uses the object-oriented methodology of the world view, the system as a series of objects set. Each object has its own responsibility, complete the independent task, the object through the message mechanism mutual cooperation, the common realization system goal. The object model is based on the concept of an object class, describing the system's objects and the relationships between those objects. The process of building an object model is called Object Modeling, which is the core technology of object-oriented modeling.

"Requirements Engineering-software modeling and Analysis" reading notes 2