基于JavaWeb的博客网站的设计与实现外文翻译(共11页).doc

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1、精选优质文档-倾情为你奉上外文原文Database Development ProcessBased on information engineering information systems planning database is a source of development projects. These new database development projects is usually in order to meet the strategic needs of organizations, such as improving customer support, impro

2、ve product and inventory management, or a more accurate sales forecast. However, many more database development project is the bottom-up approach emerging, such as information system user needs specific information to complete their work, thus beginning a project request, and as other information sy

3、stems experts found that organizations need to improve data management and begin new projects. Bottom-up even in the circumstances, to set up an enterprise data model is also necessary to understand the existing database can provide the necessary data, otherwise, the new database, data entities and

4、attributes can be added to the current data resources to the organization.Both the strategic needs or operational information needs of each database development projects normally concentrated in a database. Some projects only concentrated in the database definition, design and implementation of a da

5、tabase, as a follow-up to the basis of the development of information systems. However, in most cases, the database and associated information processing function as a complete information systems development project was part of the development. one. System Development Life CycleGuide management inf

6、ormation 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 r

7、eplacement 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 s

8、teps 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!) The system development life cycle including each sta

9、ge 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. P

10、lease note that the systems development life cycle stages and database development steps exists between the relationship between the concept of modeling data in both systems development life cycle stages between.1.1 Enterprise Modeling Database development process from the enterprise modeling (syste

11、m 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

12、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

13、 needed data. Each item only when it achieved the expected goals of organizations can be when the next step.1.2 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 divided into tw

14、o stages. First, it began the project in the planning stage. 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 (en

15、tities), 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 descrip

16、tion 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 pr

17、ocessing 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 oft

18、en 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. 1.3 Logical Database Design Logical database design from two perspectives database development. First, the concep

19、t of data model transform into relational database theory based on the criteria that means - between. Then, as the design of information systems, every computer procedures (including procedures for the input and output format), database support services, statements, and inquiries revealed that a det

20、ailed examination. In this so-called Bottom-up analysis, accurate verification of the need to maintain the database and the data in each affairs, statements and so on the needs of those in the nature of the data. For each separate statements, services, and so on the analysis must take into account a

21、 specific, limited but complete database view. When statements, services, and other analysis might be necessary to change the concept of data model. Especially in large-scale projects, the different analytical systems development staff and the team can work independently in different procedures or i

22、n a centralized, the details of their work until all the logic design stage may be displayed. In these circumstances, logic database design stage must be the original concept of data model and user view these independent or merged into a comprehensive design. In logic design information systems also

23、 identify additional information processing needs of these new demands at this time must be integrated into the logic of earlier identified in the database design.Logical database design is based on the final step for the formation of good data specifications and determine the rules, the combination

24、, the data after consultation specifications or converted into basic atomic element. Most of today's database, these rules from the relational database theory and the process known as standardization, #. This step is the result of management of these data have not cited any database management s

25、ystem for a complete description of the database map. Logical database design completed, we began to identify in detail the logic of the computer program and maintenance, the report contents of the database for inquiries. 1.4 Physical database design and definitionPhysical database design and defini

26、tion phase decisions computer memory (usually disk) database in the organization, definition of According to the library management system for physical structure, the procedures outlined processing services, produce the desired management information and decision support statements. The objective of

27、 this stage is to design an effective and safe management of all data-processing database, the physical database design to closely integrate the information systems of other physical aspects of the design, including procedures, computer hardware, operating systems and data communications networks. 1

28、.5 Database Implementation The database prepared by the realization stage, testing and installation procedures for handling databases. Designers can use the standard programming language (such as COBOL, C or Visual Basic), the dedicated database processing languages (such as SQL), or the process of

29、the non-exclusive language programming in order to produce a statement of the fixed format, the result will be displayed, and may also include charts. In achieving stage, but also the completion of all the database files, training users for information systems (database) user setup program. The fina

30、l step is to use existing sources of information (documents legacy applications and databases and now needs new data) loading data. Loading data is often the first step in data from existing files and databases to an intermediate format (such as binary or text files) and then to turn intermediate lo

31、ading data to a new database. Finally, running databases and related applications for the actual user maintenance and retrieval of data. In operation, the regular backup database and the database when damaged or affected resume database.1.6 Database maintenance During the database in the progressive

32、 development of database maintenance. In this step, in order to meet changing business conditions, in order to correct the erroneous database design, database applications or processing speed increase, delete or change the structure of the database. When a procedure or failure of the computer databa

33、se affect or damage the database may also be reconstruction. This step usually is the longest in the database development process step, as it continued to databases and related applications throughout the life cycle, the development of each database can be seen as a brief database development proces

34、s and data modeling concepts arise, logical and physical database design and database to achieve dealing with the changes. two. Information System developed by other means System Development Life Cycle minor changes in law or its variant of the often used to guide information systems and database de

35、velopment. Information System is a life-cycle methodology, it is highly structured approach, which includes many checks and balances to ensure that every step of produce accurate results, and new or alternative information system and it must communications or data definitions consistent existing sys

36、tem needs consistency. System development life cycle because of the regular need to have a working system for a long time been criticized because only work in the system until the end of the whole process generated. More and more organizations now use rapid application development method, it is a in

37、cludes analysis, design and implementation of steps to repeat the rapid iterative process until convergence to users the system so far. Rapid Application Development Act required the database has been in existence, and enhance system is mainly to the application of data retrieval application, but no

38、t to those who generate and modify database applications. The most widely used method of rapid application development is one of the prototype. The prototype system is a method of iterative development process, analysts and users through close co-operation, continuing to revise the system will event

39、ually convert all the needs of a working system. In this diagram we contains notes, briefly describes each stage of the prototype of the database development activities. Normally, when information systems problems were identified, tried only a rough concept of data modeling. In the development of th

40、e initial prototype, the design of the user wants to display and statements, and that any new database needs and define a term prototype database. This is usually a new database, copy the part of the existing system, but might also added some new content. When the need for new content, these element

41、s are usually from external data sources, such as market research data, the general economic indicators or industry standards. When a prototype of a new version to repeat the achievement and maintenance of database activities. Usually only a minimum level of security and integrity control, because a

42、t this time the focus is as soon as possible to produce a prototype version can be used. But document management project also deferred to the final, only be used in the delivery of user training. Finally, once constructed an acceptable prototype, developers, and users will be the final decision of w

43、hether to prototype delivery and the use of the database. If the system (including database) efficiency is very low, then the system and database will be re-programming and re-organization in order to achieve the desired performance. Along with visual programming tools (such as Visual Basic, Java, V

44、isual C + + and fourth generation language) increasingly popular use of visual programming tools can easily change the user interface with the system, the prototype is becoming the choice of system development methodology. Customers using the prototype method statements and show changes to the conte

45、nt and layout is quite easy. In the process, the new database needs were identified, so it is the development of the use of the existing database should be amended. There is even the possibility of a need for a new database system prototype method, in such circumstances, when the system demand in th

46、e iterative process of development in the ever-changing needs access to sample data, the construction or reconstruction of the database prototype.专心-专注-专业中文译文数据库开发过程 基于信息工程的信息系统规划是数据库开发项目的一个来源。这些开发新数据库的项目通常是为了满足组织的战略需求，例如改善客户支持、提高产品和库存管理或进行更精确的销售预测。然而许多数据库开发项目更多的是以自底向上的方式出现的，例如信息系统的用户需要特定的信息来完成他们的工作

47、，从而请求开始一个项目，又如其他信息系统的专家发现组织需要改进数据管理而开始新的项目。即使在自底向上的情况下，建立企业数据模型也是必须的，以便理解现有的数据库是否可以提供所需的数据，否则，新的数据库、数据实体和属性都应该加到当前的组织数据资源中去。 无论是战略需求还是操作信息的需求，每个数据库开发项目通常集中在一个数据库上。一些数据库项目仅仅集中在定义、设计和实现一个数据库，以作为后续信息系统开发的基础。然而在大多数情况下，数据库及其相关信息处理功能是作为一个完整的信息系统开发项目的一部分而被开发的。一. 系统开发生命周期 指导管理信息系统开发项目的传统过程是系统开发生命周期(SDLC)。系统

48、开发生命周期是指一个组织中由数据库设计人员和程序员组成的信息系统专家小组详细说明、开发、维护和替换信息系统的全部步骤。这个过程比作瀑布是因为每一步都流到相邻的下一步，即信息系统的规格说明是一块一块地开发出来的，每一块的输出是下一块的输入。然而如图所示，这些步骤并不是纯线性的，每个步骤在时间上有所重叠（因此可以并行地管理步骤），而且当需要重新考虑先前的决策时，还可以回滚到前面某些步骤。（因而水可以在瀑布中倒流！）系统开发生命周期的每一阶段都包括与数据库开发相关的活动，所以，数据库管理的问题遍布整个系统开发过程。请注意，系统开发生命周期的阶段和数据库开发步骤之间不存在一一对应的关系，概念数据建模发

49、生在两个系统开发生命周期阶段之间。1.1 企业建模 数据库开发过程从企业建模（系统开发生命周期中项目论证和选择阶段的一部分）开始，设定组织数据库的范围和一般内容。企业建模发生在信息系统规划和其他活动期间，这些活动确定信息系统的哪个部分需要改变和加强并概述出全部组织数据的范围。在这一步中，检查当前数据库和信息系统，分析作为开发项目主体的业务领域的本质，用非常一般的术语描述每个信息系统在开发时所需要的数据。每个项目只有当它达到组织的预期目标时才可以进行下一步。1.2 概念数据建模 对一个已经开始的信息系统项目而言，概念数据建模阶段分析信息系统的全部数据需求。它分为两个阶段。首先，它在项目开始和规划阶段建立一张图。同时建立其他文档来概述不考虑现存数据库的情况下特定开发项目中所需的数据范围。此时仅仅包括高层类别的数据（实体）和主要联系。然后在系统开发生命周期的分析阶段产生确定信息系统必须管理的全部组织数据的详细数据模型，定义所有数据属性，列出全部数据类别，表示数据实体间所有的业务联系，确定描述数据完整性的全部规则。在分析阶段，还要检查概念数据模型（在后面也称作概念模式）与用来解释目标信息系统其他方面的模