【简答题】概念模型通过实体-联系模型对现实世界的事物及事物间的联系给出静态描述,最终概念结构设计阶段要得到( )。
【单选题】___________is a long, allegorical poem, in which Spenser dramatized political, religious, and moral themes by personifying them, or making them characters.
【简答题】溢流阀在液压系统中所能起的作用是()、()和()。
【单选题】Doctor Spenser is _________tomorrow. Do you think it can wait until Wednesday?
【简答题】公文的行文关系是发文机关和收文机关之间的关系。公文的行文关系要根据 ______ 和 _____ 来确定。
【单选题】In the variable delivery pump, moving the spindle more from the central point will cause () fluid to be pumped and consequently ()pressure is generated to drive the rams.
【简答题】6 The odyssey years can saddle young people with enormous pressure to move forward quickly . As the sole heir and focus of their parents ' expectations , hopes and dreams , some react with rebellious ...
【单选题】在概念数据模型中,联系用于描述现实世界中事物之间的关联关系。一阿d关于联系的说法错误的是
A.
联系可用于描述一个实体集内记录之间的关联关系
C.
ER模型通过1:1、1:n和m:n三种联系描述现实世界中各类事物之间的关联关系
D.
最终的IDEFIX模型中只能出现1:1和1:n两种类型的联系
【单选题】幼儿有造血功能的红骨髓位于______内和骨松质的缝隙间。