英语翻译Data Modeling As Part of Database Design The data model

英语翻译
Data Modeling As Part of Database Design
The data model is one part of the conceptual design process.The other is the function model.The data model focuses on what data should be stored in the database while the function model deals with how the data is processed.To put this in the context of the relational database,the data model is used to design the relational tables.The functional model is used to design the queries that will access and perform operations on those tables.
Data modeling is preceeded by planning and analysis.The effort devoted to this stage is proportional to the scope of the database.The planning and analysis of a database intended to serve the needs of an enterprise will require more effort than one intended to serve a small workgroup.
The information needed to build a data model is gathered during the requirments analysis.Although not formally considered part of the data modeling stage by some methodologies,in reality the requirements analysis and the ER diagramming part of the data model are done at the same time.
Requirements Analysis
The goals of the requirements analysis are:
• to determine the data requirements of the database in terms of primitive objects
• to classify and describe the information about these objects
• to identify and classify the relationships among the objects
• to determine the types of transactions that will be executed on the database and the interactions between the data and the transactions
• to identify rules governing the integrity of the data
The modeler,or modelers,works with the end users of an organization to determine the data requirements of the database.Information needed for the requirements analysis can be gathered in several ways:
• review of existing documents - such documents include existing forms and reports,written guidelines,job descriptions,personal narratives,and memoranda.Paper documentation is a good way to become familiar with the organization or activity you need to model.
• interviews with end users - these can be a combination of individual or group meetings.Try to keep group sessions to under five or six people.If possible,try to have everyone with the same function in one meeting.Use a blackboard,flip charts,or overhead transparencies to record information gathered from the interviews.
• review of existing automated systems - if the

数据模型作为数据库设计一部分 数据模型是概念设计过程的一份.其他是作用模型.数据模型集中于什么数据应该被存放在数据库当作用模型处理怎样数据被处理.投入这就关系数据库的状况,数据模型被使用设计关系桌.功能模型被使用设计将访问和将进行操作在那些桌的询问.