面向Forms的数据库设计方法

Methodology of Form-Oriented Database Design

数据库发展至今,已经形成了较为成熟的理论和方法,但是在面向表(Forms)的数据库设计方面却尚未成熟。本文就是针对这一问题,选取面向表的数据库设计方法作为课题进行了研究探讨,产生了一种以表作为主要输入的数据库设计方法。该设计方法虽然沿用了大多数数据库设计所采用的总体设计流程,但在各设计阶段有自己的特色。文章在需求分析阶段,提出了基于表模型、表项流、表关联图三个核心概念的需求分析与描述。这样描述的信息确切、不模糊和形式化,为设计工具的产生打下了基础。在概念设计阶段,提出了概念设计的方法,即分析表的选择、初步 E—R 图的生成,以及完全 E—R 图的生成。分析表的选择确定了分析表的选择分析的先后次序。初步 E—R 图的生成阐述了从需求分析说明文档中的信息提炼E—R 图的方法。其中,包括了实体的标识及标识属性的确定、联系的确定、属性归属、联系特性的确定以及实体属籍类别的确定五个方面。完全 E—R 图的生成叙述了构造完全 E—R 图的方法。把 E—R 图映射成关系表是本文在逻辑设计阶段所讨论解决的问题。在探讨设计方法的同时,本文以一个实例,说明了设计方法的具体地实施情况。

Up to now,theories and techniqes of database has become somewhat mature,but the methodology of form oriented database design is still a developing field. In view of this situation,The article strengthen research on a new method for form oriented database design,benefits from traditional database design methods.The reguirements analysis and speci- fications are centered around form model,form field flow,and form related graph to obtain a formal, concise and unambiguous representation manner.The conceptual design is divided into three steps,that is form selection,partially completed E—R diagram generation and completed E—R diagram genera- tion.Form selection determines the order of analyzing forms.Partially completed E—R diagram genera- tion produces E—R diagrams from requirements analysis and specification documents.The whole pro- cess consists of entity identification,relationship identification,attribute attachment,relationship cardi- nality identification,and entity membership class identification.Completed E—R diagram generation provides methods to get completed E—R diagram.The logical design discusses how to map E—R dia- grams to relation tables.A example is used to demonstrate the application of this methodology.