The book is divided into a total of four parts, each part has a need to be careful and need to learn the reality of the project encountered do comparison, this is the first time I try to do the book summary.
- Basic system analysis and design
- System Analysis
- system design
- System construction and implementation, and after work
1. The basic system analysis and design
The system has five key elements: life-cycle stage system type, system participants, business drivers, technology drivers for the system. These five elements can analyze the composition of the system in the general direction of, look at the system from the perspective of three different starting points, three starting points are: business knowledge, business processes, business communication. The viewing angle can be observed at all stages of the life cycle of the system. System development process Capability Maturity Model can be used to adjust, and the development process to follow some basic principles of development, such as the early detection of problems and timely modification, etc., and then develop strategies, such as model-driven strategy, rapid application development strategies. Among the systems analysis and design project management is the most important of the top field, when a large part of the project failed because of system requirements analysis phase to obtain a problem, of course, there are other reasons.
2. System Analysis
A common method is to analyze the system model-driven analysis method, analysis acceleration system, etc., regardless of the method are analyzed in order to accelerate the process. Process analysis system generally as follows:
- The first step, the scope of the definition phase, deliverable is the project charter, a simple analysis of the project is not worth it
- The second step, problem analysis phase, deliverable is the feasibility study report, in-depth research to solve critical issues
- The third step, requirements capture phase, deliverable is the project needs, need to adopt various needs access to technology, access and organize to demand
- A fourth step, the logical design phase, deliverable various logic design, only needs UML modeling tools and how to validate
- The fifth step, decision analysis phase, deliverable is the feasibility of the proposed program, mainly to do comparison and decision-making on the feasibility
In general, projects need to cut or make adjustments according to the process of adaptation to meet the real needs of the project. Project Charter stage is the point of whether the first inspection of the project to proceed. Feasibility report of speaking in different books are different, but the essence is the same, including: organizational feasibility, economic viability, technical feasibility, operational feasibility, environmental feasibility, legal cultures and political feasibility, risk assessment. Each must assess the feasibility of direction, at the same time for each program also evaluate the feasibility of these aspects. In general can capture requirements through: documentation, research and field visits to observe the work environment, questionnaires, interviews, prototyping, technical and other joint requirements planning is completed, the contents of this part of the cost, the documentation is the lowest way , the interview is the most expensive. Logical design phase need to design using UML use case diagram, each requirement verification is not consistent understanding, followed by the data model design, then the process model, and finally the synchronization of the data and process models. Performing a logical design process, follow the principle of the system as analyzed, decomposed with the embodiment can be modeled reprocessed.
3. System Design
System design common method is model-driven, rapid application development. General system design process is as follows:
- The first step, like the interaction between the application framework design, all physical nodes on the system design of the whole system, the system
- The second step, database design system
- The third step, system interface design
- The fourth step, packaging design specifications, design documents to archive all kinds of achievements
- The fifth step, a revised project plan, according to the information to adjust the design of the project plan
Implementation of programs designed to take two, independent research and development and procurement outsourcing, and sometimes there will be a combination of both. Application framework is designed to start a data flow diagram of a system analysis logic design stage into a physical data flow graph, then the combined pre-conditions, and then the network is designed to determine the network of the system, followed by data distribution and data technology selection and then the next process technology selection and distribution, and finally determine the man-machine boundary. Design of the whole application framework is from a logic design into a physical design, physical design is much higher than the range or the scope of the software design. Database design, we must first consider the issue of file storage and database storage, that is more appropriate. If you use the database design, we generally follow: determine a goal and database design constraints; select the appropriate database schema, is the choice of mysql or oracle; setting access data integrity and completeness, we do not need to check the data and cascaded operation; common character set permissions database, of course, contains the character; distributed and replicated databases, and select the physical location of the database backup; generating a prototype database, the data can easily test and maintenance; capacity planning database, based on the actual traffic data is growing capacity adjustment, including adjustment and a sub-table data structure; and finally generate the database structure, the structure of the database application is a basic system operating conditions are met, including the initialization data base. The system comprises a design interface design output, the input design, user interface design. The design of this part to follow a number of requirements, design to different output adjusted according to the position of the output, such as internal output, the external input, output, rotation; input design data collection must be followed not now stored or calculated out of the system, only able to collect useful data, data entry validation reasonable to do; the user interface is designed to meet the operational requirements of the people, ergonomics can give some guidance to optimize the user experience. Interface is a general design process: the need for conversion from the physical design of the logic design; selecting an appropriate physical design components; physical layout and style of the adjustment assembly; if necessary is generated by the source file archiving; and finally to the user reviews make improvements.
And after the work implement 4. The system configuration and
By the previous description we all know the basic structure of the system is ready to do anything. The system packages sucked structure to achieve complete deployment into the production environment to run. General process of system implementation are: system testing, functional testing done to verify the system's normal operating normally, of course, in a test environment; preparation and implementation of the conversion plan, this stage is mainly to do the conversion of the old and new systems, system verification test will be carried out this test includes verification testing, validation testing, audit tests; install the database, do the conversion of old and new databases; finally, user training, because most users are not it kind of technology, so be carefully considered in this training material details of the communication. After the formal operation of the system, there have been a common knowledge Context system, application system database, code libraries, business databases. Follow-up work should be carried out based on this background. General process of system operation and maintenance are: discover the problem, to confirm; to test the program, find the code library version problem occurred; research, commissioning, repair problems; the test program. Follow the on-line system improvements in general are new features, update a wide range of basic is not, unless there is complete data information and professional IT staff, or else how will 20 years ago, the code is still running, no one dared to touch it too!