System analysis and software modeling
Source: Institute of Management of the network project: nine
If the vision is only to meet the needs of our customers, when the problem continues to make, the headache mentions, the pedicure, and even the system architecture needs to continuously adjust or redesign, then, will soon fall into the code quagmire or fall In the absence of repeated development of the system, the sense of accomplishment when the project is completed will be replaced by endless depression. Systematic analysis determines the success or failure of system development, software modeling makes system development to mature. This chapter includes the following: 1: Systematic status in website project management 2: System analysis to do three: Difficulties and skill requirements for system analysis 4: Software modeling makes system development to mature five: summary 1: System Analysis of the status of the website project management is extremely important after performing demand analysis and business process analysis and customer recognition, it is extremely important. System analysis is a document that can reflect the soul of the entire system, and the needs of customers from a specific to abstract process, and formulate specifications and standards that coders can implement. Due to the history of the development of Web application technology, the design staff often pays attention to system analysis in system design, especially in system design, especially in terms of development, especially in terms of development network applications, especially website production, especially in terms of design, simple or interactive. When there are fewer features, the main reasons are usually:? The need for the initial demand is relatively simple, ignoring the potential huge demand for customers; "The project implementation cycle is short, the fastest instead of the initial phase is the fastest rather than the most reasonable means; Limited, it is difficult to pay high quality human expenses; the web programming technical means is diverse, easy to get started, the designer is uneven; from reality, the development and management and implementation of website projects are far less than software engineering norms, in programming language, Both related environments such as databases, communication protocols, application servers are constantly developing and improving, and it is difficult to expect every designer's website project for systematic reasonable analysis, thereby formulating a set of cross-platform, robust, Easy to expand and upgrade system solutions. However, this does not become an excuse of the system analyst escape or slack. If a system is more than a car, the system analysis work is equivalent to design engine, maybe it is easy to imagine 125cc motorcycle engine to pull 10 What kind of consequences will be a ton heavy load truck. In the process of system analysis, further deepening and analysis of demand analysis, usually customer and business personnel pay more attention to functional performance and definition in the process of demand analysis and process analysis, even for formal user interface prototypes, The demand for the system is incomplete. It is difficult for non-technical personnel. It is difficult to make a complete and clear professional performance demand, but it does not mean that this demand does not exist, and this hidden demand is extremely important for the coder. of. Therefore, whether the customer's demand can be realized and implemented in the system, and systematic analysis is critical. 2: System analysis to do: separate system analysis and detailed design stages, and decide what to develop in terms of different projects. Then focus on system analysis: • Further improve and supplement the needs of customers, especially performance requirements: let customers know more about this is a system, what is the function and performance indicators you want, How the system is extended and adaptive, how to provide the most effective way for customers future upgrades or maintenance. • The environment you need to run in system: The system can run the hardware, software, network environment required for the system; system's resource description: the various costs required for the system. Including all resources such as personnel, time, work environment, one-time investment, sustainable investment.
System feasibility analysis; for system analysts, most customers can't mention independent or mature opinions on the system's requirements, and handing hot mood over the system analyst, in order to avoid system argumentation It is difficult to grasp the out-of-control and unwaver, design several different types of solutions for customers to choose a good way: "For example, at least consider at least the following possible solutions: 1: Low cost solution system can only be completed The most necessary work is not possible to do more work. 2: Sino-cost solution This system can not only complete the predetermined task well, it is very convenient to use, and may also have some functions that users do not specify specific specified. And characteristics. Although the user did not propose these specific requirements, the system analyst decided according to its own knowledge and experience, these additional capabilities will prove very valuable in practice. 3: High-cost "Ten Duple Tenth Beauty" system The system has all functions and features that users may want. System analysts should use system flow charts or other tools to describe each possible system, estimate the cost and benefits of each program, but also to weigh the pros and cons of various programs. Based on, a better system (best solution) is recommended and develop a detailed plan for the recommended system. If the user accepts the system recommended by the analyst, you can start the other main work in this stage. " Reference "How to write system analysis" One article "After systematic analysis, we are more likely to meet how customers have reached how to deploy, the database type, design model, and analysis model use, if you can successfully Demand business logic analysis transforms to program logic, map the original user visual interface prototype and business process map to the model and specification of the codent's understanding, then congratulations, the project has been successful. Three: Difficulties and skills of system analysis require development technologies for network applications to advance in the day, so that the development model of the website application system has a variety of selectivity, and achieving the same goal can adopt a lot of different ways, and modern application systems are increasing. More a huge integrated solution, you need to consider different operating platforms, different application servers, different databases, different programming languages, different transmission media, etc., undoubtedly a serious test for system analysts, anyone It is impossible to master all the technology, simple example: There are all server operation platforms such as Windows, UNIX, Linux, SQL Server, Oracle, DB2, Sybase, MySQL, etc., there are Java, PHP, ASP, CGI , JSP, C , VB, Delphi, etc., who can be fine? If you can't, how do you determine whether Windows SQL Server ASP is good or Unix Oracle Java is appropriate? Moreover, the various software and language are still evolving in progress, transcending narrowband Internet, can also involve changes in broadband, or increase the interface with wireless movement, so system analysts can exceret the work To a large extent, the success or failure of system development is determined. The main difficulty of system analysis is: • Analysis of performance requirements for customers: Because customers are not expected, the future business development is impossible, and the analysis and definition of performance requirements requires system analyst to assist customers. Determine and excavate; • Determine the project design method: Select the most appropriate design based on project requirements and resources.
• Design for the division and code multiplexing of the system module: Maximum module, the highest code reset is the ripening system, constantly pursuing the pursuit of the large complex application system into a relatively independent, highly multiplexed module. The parameters interfaces are used between each module, which will greatly improve the development efficiency of the system and the convenience of maintenance and upgrading. Even in the template design or interaction design of the website, you can use nested template or call unified style sheets, JS files, etc. • The overall assessment of the project: The system analyst should never be an isolated perfectionist, but it is necessary to start according to the overall situation of the project, such as the company's resource allocation, manpower, customer requirements and other factors to assess the workload of the project overall and various modules. And allocate resources to develop the most reasonable and viable implementation. System analysts not only need to have good communication and coordination, but also need professional skills in business and technical fields, and is one of the very important roles in the project team. IV: Software modeling makes system development towards mature web applications often grows with customers, development is constantly in-depth, and ultimately become very complex, and Web-based website systems usually have high dynamic expansion and interaction, It is extremely difficult to complete a robust system that is easy to modify and maintain in a limited time in a limited time, in a limited time, is extremely difficult to appear in UML (unified modeling language). Most web designers or procedures developers directly enter the coding stage after the interface design or simple system analysis is used as soon as possible. Even each module is developed, and the server segment code is free to add. The parameter definition is not specified, and the entire application system is in a state of disorderly confusion. When we use modeling and in accordance with software engineering, it will be much better. What is modeling? Modeling is a way to solve problems by layers by layer;? Confirm the functional requirements of the application system and model the transaction principles;? Abstract object map demand, identify and provide design template and create a customary template; And design objects or partitions of the three-layer model;? Map the components of the software into objects and design how components are distributed on the network; UML (Unified Modeling Language, Unified Modeling Language) is a general visual modeling language, Used to describe, visualize, construct, and establish documents of software systems. UML is suitable for a variety of software development methods, various stages of software life cycle, various application areas, and various development tools. Similarly, in various network application projects designed or in the form of a website, UML also shows powerful. Role. UML can describe the static structure and dynamic behavior of the system: the static structure defines the properties and operations of important objects in the system, and the interrelationship between these objects; dynamic behavior defines the time characteristics of the object and the object to communicate with each other. Mechanisms. UML is not a programming language, but we can use the code generator to convert the UML model to a variety of programming language code, or convert the program source code to the UML model using the reverse generator tool. What we can see, modeling is not equivalent to program coding, using the same UML model to generate framework code of different languages, and can be generated in reverse generation, updating UML model in time during writing code, this for system analysts And project managers are dreaming. As long as you can carefully grasp the customer's needs, constantly improve the UML model, then what kind of language development has become secondary, a large number of demand accumulation and analysis work can be highly reused when customer demand changes, even if the system adopts new The language is re-developed, and it is only the work of the encoding part.
