During the systems analysis phase,you must decide how data will be organized,stored,and managed. A (71)________ is a framewor

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问题 During the systems analysis phase,you must decide how data will be organized,stored,and managed. A  (71)________  is a  framework for organizing,storing,and managing data.Each file or table contains data about people,places,things,or events.One of the potential problems existing in a file processing environment is  (72)________,which means that data common to two or more information systems is stored in several places.In a DBMS,the linked tables form a unified data structure that greatly improves data quality and access.A(n)(73)________  is a model that shows the logical relationships and interaction among system entities.It provides all overall view of the system and a blueprint for creating the physical data structures.(74)________ is the process of creating table designs by assigning specific fields or attributes to each table in the database.A table design specifies the fields and identifies the primary key in a particular table or file.The three normal forms constitute a progression in which  (75)________  represents the best design.Most business-related databases must be designed in that form.
(75)

选项 A、standard notation form
B、first normal form
C、second normal form
D、third normal form

答案D

解析 在系统分析阶段,需要确定数据如何组织、存储和管理。数据结构是用于组织、存储和管理数据的一个框架。每个文件或表中包含了关于人物、地点、事物和事件的数据。文件处理场景中存在的潜在问题之一是数据冗余,意味着两个或多个信息系统中相同的数据存储在多个不同位置。   
在关系数据库管理系统(DBMS)中,相互链接的表格形成了一个统一的数据结构,可以大大提升数据质量和访问。实体联系图是一个模型,显示了系统实体之间的逻辑关系和交互。它提供了一个系统的全局视图和用于创建物理数据结构的蓝图。规范化是通过为数据库中的每个表分配特定的字段或属性来创建表设计的过程。表设计是在特定表或文件中确定字段并标识主关键字。三种范式构成了一个序列,其中第三范式代表了最好的设计,大部分与业务相关的数据库必须设计成这种形式。
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