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A view is created with the following statement:CREATE VIEW v1 AS SELECT col1, col2, col3, col4 FROM t1 WHERE col4 > 1000 WITH CHECK OPTIONWhat is the effect of the CHECK OPTION clause?()
A . Any row inserted or updated through view V1 must meet the condition that col4 > 1000.
B . From now on, any row inserted or updated in table T1 must meet the condition that col4 > 1000, but existing rows in the table are not checked.
C . At view creation, DB2 will check the data in table T1, and if in any row doesn't meet the condition col4 > 1000, the view creation will be rejected.
D . Any row inserted or updated through view V1 must meet the condition that col4 > 1000 and no row in table T1 can be updated such that col4 <= 1000, but new rows in the table can be inserted with col4 <= 1000.
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Tools with ()handles should be used to check electric circuit.
A . plastic
B . metal
C . stainless steel
D . copper
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在Oracle中,建表约束包括引用完整性约束、check完整性约束,还有以下三项是正确的,请排除一个错误选项。()
A . A、非空完整性约束
B . B、唯一完整性约束
C . C、主码完整性约束
D . D、数据角色性约束
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在使用CHECK约束时,以下注意事项中正确的是()。
A . 使用INSERT语句时,系统不进行CHECK约束检查
B . 使用DELETE语句时,系统进行CHECK约束检查
C . 一个列上可以包含多个CHECK约束,它们之间是“AND”或“OR”的关系
D . CHECK约束不能定义在指定IDENTITY属性或数据类型为timestAmp的列上,且CHECK约束不能包含子查询语句
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下列选项中,()是由业主大会制定,全体业主承诺,对全体业主具有约束力的,用以指导、规范和约束所有业主、物业使用人、业主大会和业主委员会权利义务的行为守则。
A . 服务标准
B . 管理规约
C . 临时管理规约
D . 物业服务合同
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Before sailing,mariners on duty shall check the headings of magnetic compass by comparison with().
A . ship's clock
B . engine movement recorder
C . repeaters
D . navigation light
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规则对象在使用上与CHECK约束类似。
A . 正确
B . 错误
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CHECK约束的作用是()
A . 维护数据的实体完整性
B . 提高数据录入效率
C . 限制列的取值范围
D . 提高数据修改效率
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CHECK约束被称为()约束,UNIQUE约束被称为()约束。
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Check约束可以实现()
A . 限制一个表中单个列的取值范围
B . 限制一个表中多个列之间的取值约束
C . 限制不同表之间列的取值约束
D . 为列提供默认值
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Whilst the engine is turning, check to see that no water is leaking into the crankcase, scavenge air belt, or from ().
A . exhaust valves
B . starting valves
C . fuel valves
D . the indicator cock
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在为已有数据的表添加CHECK约束时,在建立约束前()
A . 系统不检查表中数据是否符合约束,直接建立约束
B . 系统先检查表中数据是否符合约束,符合约束时才建立约束
C . 系统先检查表中数据是否符合约束,不符合约束时给出提示信息并建立此约束
D . 系统先检查表中数据是否符合约束,并删除不符合约束的数据,然后建立约束
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Check the reasons why Jason feels satisfied with his present job.
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The guest needs to check back with the receptionist tomorrow.
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When we deal with check-in, signing the register is one of the important procedures .
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When we deal with check-in, signing the register is one of the important procedures.
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不论用户选择的约束对象是何种类型,约束定义对话框当中的所有选项都是全部可用的,用户可以根据需要进行自由定义。( )
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进行草图分析时,单击“草图分析”对话框的“诊断”选项卡,其列表框中显示草图中所有的几何图形和约束以及它们的状态。()
是
否
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CHECK约束通过限制输入到列中的值来强制域的完整性
是
否
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下列选项中可以暂停办理退税的有()。
A.存在增值税涉税风险疑点的
B.被税务稽查立案且未结案的
C.增值税申报比对异常未处理的
D.取得增值税异常扣税凭证未处理的
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5种约束类型,即PRIMARYKEY(主键)、FOREIGNKEY(外键)、UNIQUE(唯一性)、CHECK(取值范围)和DEFAULT(默认值)约束()
是
否
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check约束通过限制输入到列中的值来强制域的完整性,对单独一列可使用多个check约束()
是
否
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创建学生用check(age<30 and age>17)进行约束,这属于数据库()完整性约束
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Directions: Listen again and check the reasons why Jason feels satisfied with his present job.
A.He has a big office
B.He is well-paiD
C.His boss is open-minD
D.His colleagues are helpful.
E.His job provides good opportunities for promotion.
F.There is not much pressure at his work.
此题为多项选择题。