Information System Development and Database Development 2。1 System Development Life Cycle Guide management information system development projects is the traditional process of system development life cycle (SDLC)。 System development life cycle is an organization of the database designers and programmers information system composed of the Panel of Experts detailed description, development, maintenance and replacement of the entire information system steps。 This process is because Waterfall than for every step into the adjacent the next step, that is, the information system is a specification developed by a piece of land, every piece of the output is under an input。 However shown in the figure, these steps are not purely linear, each of the steps overlap in time (and thus can manage parallel steps), but when the need to reconsider previous decisions, but also to roll back some steps ahead。 (And therefore water can be put back in the waterfall!) 72081

Figure 4 on the system development life cycle and the purpose of each stage of the product can be delivered concise notes。 The system development life cycle including each stage and database development-related activities, therefore, the question of database management systems throughout the entire development process。 In Figure 5 we repeat of the system development life cycle stage of the seven, and outlines the common database at each stage of development activities。 Please note that the systems development life cycle stages and database development steps一一对应exists between the relationship between the concept of modeling data in both systems development life cycle stages between。 

Enterprise Modeling 

Database development process from the enterprise modeling (system development life cycle stage of the project feasibility studies, and to choose a part), Organizations set the scope and general database content。 Enterprise modeling in information systems planning and other activities, these activities determine which part of information systems need to change and strengthen the entire organization and outlines the scope of data。 In this step, check the current database and information systems, development of the project as the main areas of the nature of the business, with a very general description of each term in the development of information systems when needed data。 Each item only when it achieved the expected goals of organizations can be when the next step。 

Conceptual Data Modeling 

One has already begun on the Information System project, the concept of data modeling phase of the information systems needs of all the data。 It is pided into two stages。 First, it began the project in the planning stage and the establishment of a plan similar to Figure 1。 At the same time outlining the establishment of other documents to the existing database without considering the circumstances specific development projects in the scope of the required data。 This category only includes high-level data (entities), and main contact。 Then in the system development life-cycle analysis stage must have a management information system set the entire organization Details of the data model definition of all data attributes, listing all data types that all data inter-entity business linkages, defining description of the full data integrity rules。 In the analysis phase, but also the concept of inspection data model (also called the concept behind the model) and the goal of information systems used to explain other aspects of the model of consistency categories, such as processing steps, rules and data processing time of timing。 However, even if the concept is such detailed data model is only preliminary, because follow-up information system life cycle activities in the design of services, statements, display and inquiries may find that missing element or mistakes。 Therefore, the concept of data often said that modeling is a top-down manner, its areas of operation from the general understanding of the driver, rather than the specific information processing activities by the driver。