Chapter 11 Database Management 11.2 DBMS STRUCTURING TECHNIQUES DBMS iS able to access and retrieve data from nonkey record fields. That is the dbms is able to structure and tie together the logically related data from several large files DBMS可综合几个文件的数据项以回答用户对信息的查询,这就意味着 DBMS能够访问和检索非关键记录字段的数据,即DBMS能够将几个大文件 中逻辑相关的数据组织并连接在一起 Logical Structures. Identifying these logical relationships is a job of the data administrator. a data definition language is used for this purpose. The DbMs may then employ one of the following logical structuring techniques during storage access, and retrievaloperations Ill 逻辑结构。确定这些逻辑关系是数据管理者的任务,由数据定乂语 言完成。DBMS在存储、访问和检索操作过程中可选用以下逻辑构造技术 《什第机专出美语 1-10Chapter 11 Database Management 计算机专业英语 11-10 11.2 DBMS STRUCTURING TECHNIQUES DBMS is able to access and retrieve data from nonkey record fields. That is, the DBMS is able to structure and tie together the logically related data from several large files. DBMS可综合几个文件的数据项以回答用户对信息的查询，这就意味着 DBMS能够访问和检索非关键记录字段的数据，即DBMS能够将几个大文件 中逻辑相关的数据组织并连接在一起。 Logical Structures. Identifying these logical relationships is a job of the data administrator. A data definition language is used for this purpose. The DBMS may then employ one of the following logical structuring techniques during storage access, and retrieval operations[1] : 逻辑结构。确定这些逻辑关系是数据管理者的任务，由数据定义语 言完成。DBMS在存储、访问和检索操作过程中可选用以下逻辑构造技术: