First, the formation of system development methods
The formation of system development method concepts and people began to start the study of system development methods began around 1960. The development method of the early study information system is mainly starting from two aspects: one is from the development of a large software engineering; the other is to develop an angle suitable for the actual needs of management. What we are discussing now is a information system development method that integrates both.
EDP produced in the 50-260, there is a very good place in the development process, how to fully and reasonably organize a large application software system, two of which are: how to reasonably when designing the system Division system, and organize multiple manpower to work together, and how to reasonably consolidate the work made by many developers when system implementation. In the 1960s, Constantin, Larry L.Constantine, made the top-down, structured system development method, which contributed to:
1. Created the first river of system development methodology
The core of this method is to divide the development of the entire application software system into three phases: problem analysis, system design and programming implementation. The first two phases use the Top-Down method to structureively divide, analyze and design a system, and the next stage uses the Bottom-Up method, according to the first two phases. The result of the design, starting from the most basic layer module, one by one, and then gradually spraying into an overall system according to the structure. Since this research is from how to develop a large-scale application software system, it is generally, so it is considered to be the beginning of system development methodology.
2. Application of system approach in software development
In the 1950s, the system is the foundation and development of the system, and the idea of systemism is widely used in various fields. In addition to some certainty structural models and quantitative description models, it is widely used to explain almost all things in addition to some certainty structural models and quantitative description models. The founder of systemism Betarangfi (L. V. Bertranffy) believes that systemism is in a sense that the scientific exploration of "overall" and "overall". Under the guidance of this front-tuning system view, the agreement, Constantine, Dimoco and others have cleaves it to combine it with the development process of large software systems, and evolve it into a kind of top The software analysis design method, that is, the analysis of the problem and software must adhere to the principle of topical part of the whole, and only have partial optimization in the overall optimal situation. Under the premise of ensuring global, the system is divided into the system, so that the system is divided into a number of other organic contacts and independent subsystems (or modules), then push, layer segmentation until finally complete the entire System analysis and design.
3. Engineering development software
Developing large-scale software engineering is one of the main means of solving the problem of structuring system development methods with engineering methods and methods. Developing a software system is an effective way to develop a software system is not a structure development method, but a effective approach that has been used in a large engineering project (including software engineering). The main contribution of structured development methods is to solve engineering development methods and self-destruction system ideas, structured systems, and better solve large software system development, individual work and group work. relationship.
The engineering method emphasized in structured system analysis is:
First, the development process is divided into many engineering development phases and steps, such as feasibility analysis, problem analysis, system design, programming implementation, and more.
Second, in each development step, there are many engineered charts to plan, record and express developers' work in this step. These charts include two parts: a part is a flowchart and deconstruction, which is similar to a general drawing; another part is a program document file, primarily to explain some details in programming, so that it is convenient for future maintenance and modification.
Second, the development of development methods
Some development methods have been studied from different perspectives to jointly promote the formation and development of system development methods. More representative examples are: Jackson development methods from JSP to JSD, combined with structural development methods and demand definitions, information system engineering methods, and subsequent information system development engineering specifications, prototype methods, OO method, Case method, etc. Jackson system development method
The Michael Jackson system development method started from the research program design method. In 1975, Jackson proposed a systematic programming method in its "program design principle", which is called a structured program method (JSP). In 1983, Jackson promoted JSP to the entire system development area in "System Development", so as to the Jackson System Development Method (JSD). JSD is a method of describing and implementing a computer system. Applications include demand description, function description, logical system design, application system design, physical system design, program description, design, program implementation, and system maintenance.
2. Information Engineering
Information engineering is an engineering approach that Martin and Finkeletein in its intention of "Information Engineering" have a comprehensive support for information system development processes. It is a method based on data and data relationships, user-driven methods. The contents of information engineering methods include: strategic demand planning, data modeling and standardization analysis, process formation, data use analysis, implementation strategy, distribution analysis, physical database design, fourth generation language, program description synthesis, etc.
We briefly review the development process of information system development methods in time. The four types of methods are summarized as shown in Table 1 according to the programming method, software engineering method, management / demand analysis method, and automation system development methods.
Table 1
Era 70 80 90 Programming Method SP Method JSP Method Software Engineering Method SADT Method JSD Method Prototyping Method OO Method Management / Demand Analysis SRD Method BSP Method CSFS Method Automation Development Method CASE Method
Where STRUCTURED Program is a structured program method, JSP (Jackson structured program) is Jackson structure program, JSD (Jackson System Development) is Jackson System Development Method, SADT (STRUCTURED Analysis & Design Technology) is a structured system analysis and Design technology, prototyping is the prototype method, OO (Object Oriented) is an object-oriented development method, SRD (Structured Requirements Defination) is a structural demand definition method, and BSP (Business Systems Planning) is commercial system planning, CSFS (Critical Success Fastors) ) For key success factor law, CASE (CComputer Aided Software Engineering) is a computer-aided software engineering method.
