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参照完整性规则
时间：2021-12-27 11:29
关键词：
计算机数据库系统原理
计算机科学技术
大学试题
工学
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<p> 这条规则要求“不引用不存在的实体”。其形式定义如下：如果属性集K是关系模式R1的主键，K也是关系模式R2的外键，那么R2的关系中，K的取值只允许有两种可能，或者为空值，或者等于R1关系中某个主键值。</p>
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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.
A cabinet or space containing the controls or valves for the fixed firefighting system must be（）.
A cabinet or space containing the controls or valves for the fixed firefighting system must be（）.
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CASE OF DEATH OR SERIOUS INJURY TO A PERSON IN AN ACCIDENT OR SHIPPING DISASTER is（）.
Mainly east 3 or 4 partly cloudy to overcast occasional rain（）slowly south moderate or good.
病例对照研究进行统计性推断时不匹配分层资料总的OR值计算公式是
（）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.
Damage to cargo caused by fumes or vapor from liquids,gases, or solids is known as（）.
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
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.
If he is a common carrier，he is absolutely responsible to the owner of the goods carried （）any loss or damage to them unless caused by an Act of God or the Queen’s enemies，or the inherent vice in the goods themselves，or the negligence of the owner of the goods，or a general average sacrifice.
系统中雷达状态包括Unknown、Operational（or ON）、Failed（or OFF）、Detached。
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