Software Engineering Fifth Chapter Knowledge Point Summary _ software project

The fifth chapter overall design 1. Design process, the overall design is usually composed of two stages: System design phase: To determine the specific implementation of the system; Structure design phase: Determine the software structure. 2. The Nine Steps (1) of the overall design envisage alternative programmes, platforms, and technical certainty, using newer technical programmes as far as possible. (2) Choosing a reasonable scheme, usually at least selecting a low cost, medium cost and high cost three solutions (3) recommend the best solution (4) function decomposition, function decomposition leads to further refinement of the data flow diagram, but also should use the IPO map or other appropriate tools to briefly describe and refine each processing algorithm (5) Design software structure, Software architecture is a hierarchical system composed of modules, you can use a hierarchy or structure diagram to describe (6) Design database, physical parameters, library attempts, stored procedures, custom functions, database tables (7) Develop test plans, functional testing, integration testing, acceptance test plan test methods: Black/White Box Path testing, etc. (8) Writing document: Schematic design Manual system description User Manual test plan detailed implementation plan Database design Structure (9) Review and Reexamination 3. Modularization: Dividing the program into separate named and independently accessible modules, each module completes a child function, integrates these modules to form a whole, can complete the specified function to meet the user's needs. 4. Abstract, some similar aspects (commonalities), the convergence and generalization of these similar aspects, temporarily ignoring the differences between them, this is the abstraction. The only effective way to deal with complex systems is to construct and analyze it 5 in a hierarchical way. The Miller rule of refinement: A person can only focus on (7+-2) a block of knowledge at all times 6. Localize, put some closely related software elements physically close to each other. Using localized data elements in a module is an example of localization. The localization of the localized error handling used by the variable (the variable is defined within the function) 7. Concealment means that effective modularity can be achieved by defining a set of independent modules that Exchange only 8 of the information that must be exchanged in order to complete system functions. Module independent Single module single function Cohesion well-structured classes low coupling 9. Heuristic rules for high quality software design (1) Improve the software structure to improve module independence (2) module size should be moderate (3) depth, width, Fan out and fan in should be appropriate (4) module scope should be within the control domain (5) Strive to reduce the complexity of the module interface (6) Design single entry single exit module (7) module function should be predictable