首页/ 题库 / [单选题]数据库的三级模式之间存在的映像关系正确的的答案

数据库的三级模式之间存在的映像关系正确的是( )。

单选题
2021-07-17 23:12
A、外模式/内模式
B、外模式/模式
C、外模式/外模式
D、模式/模式
查看答案

正确答案
B

试题解析

相关题目
boost的意思是:help or encourage to increase or improve
eloquent的意思是:fluent or persuasive in speaking or writing

A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.

如果分别以检索词a、b、c在某数据库的关键词字段进行检索,检索式a or b and c得到检索结果数量最少。
()any case or suspected case of quarantinable disease,or any case of eruptive disease or any death be discovered,the local quarantine officer must be notified immediately.
Should any case or suspected case of quarantinable disease,or any case of eruptive disease or any death be discovered,the local Quarantine Officer must be()immediately.
已知A=40;B=30;C=100;D=50,逻辑“与”运算符为and,“或”运算符为or,“非”运算符为not。计算表达式(A>B+20)or(B+60<>
设a=5,b=4,c=3,d=2,则表达式3>2*b Or a=c And b<>c Or c>d的值是
设a=5,b=4,c=3,d=2,则表达式3>2*b Or a=c And b<>c Or c>d的值是
Masters are()solely responsible for all damages or accidents of whatever kind resulting from the navigating or handling of their vessels by day or by night.
系统中雷达状态包括Unknown、Operational(or ON)、Failed(or OFF)、Detached。
数据库技术是现代信息科学与技术的重要组成部分,是计算机数据处理与信息管理系统的核心。
The carrier is liable for loss of or damage to the goods or delay in delivery caused by fire,()the claimant proves that the fire arose from fault or neglect on the part of the carrier,his servants or agents.
Shutdown price(or point,or rule) 停业价格(或停业点、停业原则)
设a=2,b=3,c=4,d=5,表达式3>2*b or a=c and b<>c or c>d的值是( )
设a=5,b=4,c=3,d=2,则表达式3>2术b Or a=c And b<>c Or c>d的值是
设a=5,b=4,c=3,d=2,下列表达式的值是 3>2*b Or a=c And b<>C Or c>d
设a=5,b=4,c=3,d=2,下列表达式的值是( )。 3>2*b Or a=c And b<>c Or c>d
设a=5,b=4,c=3,d=2下列表达式的值是 3>2*b Or a=c And b<>C Or c>d
设a=5,b=4,c=3,d=2,下列表达式的值是 3>2*b Or a=c And b<>c Or c>d
广告位招租WX:84302438

免费的网站请分享给朋友吧