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【单选题】
在关系代数的连接操作中,哪一种连接操作需要取消重复列? ( )
A.
自然连接
B.
笛卡 尔 积
C.
等值连接
D.
θ连接
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参考解析：
知识点：
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举一反三
【多选题】1980年纪念陈垣诞辰结集的文集分别是
A.
陈垣校长诞辰百年纪念文集
B.
纪念陈垣诞辰一百周年史学论文集
C.
励耘书屋问学记
D.
其他
查看完整题目与答案
【判断题】为了防止直接触及带电体，通常采用漏电保护器、保护接地或接零等技术措施。
A.
正确
B.
错误
查看完整题目与答案
【简答题】阅读理解。 School education is very important and useful. The students both learn knowledge and get an education. Yet, no one can learn everything from school. The scientists (科学家) , such as Edison, Newton...
查看完整题目与答案
【单选题】燃烧时有大蒜样臭气的是
A.
信石
B.
赭石
C.
石膏
D.
硫黄
E.
雄黄
查看完整题目与答案
【简答题】Today, no one thinks of Bill Gates as a failed entrepreneur or a college dropout yet. Both of these things are true of Gates, American richest man and the pioneering genius who leads the computer soft...
查看完整题目与答案
【简答题】主要知识点: 1、背景图的插入与调整; 2、控制点曲线与内差点曲线的转换; 3、直线挤出,注意曲线的组合; 4、旋转阵列复制; 5、投影曲线
查看完整题目与答案
【简答题】阅读理解 School education is very important and useful. The students both learn  knowledge and get an education. Yet,no one can learn everything from school. The scientists, such as Edison, Newton, Galile...
查看完整题目与答案
【多选题】彩陶分布很广，在黄河上游有河南、河北、山西、陕西等地的(    )，黄河下游有(    )。
A.
仰韶文化    
B.
大汶口文化  
C.
河姆渡文化  
D.
屈家岭文化
查看完整题目与答案
【单选题】相对论主要是由谁创立的?
A.
爱因斯坦
B.
门捷列夫
C.
法拉第
D.
祖冲之
查看完整题目与答案
【单选题】I thought of God as a strangely emotional being. He was powerful He was forgiving yet obdurate, full of warmth and affection. Both His wrath and affection were fitful, they came and they went, and I c...
A.
had been born in natural surroundings with banks and churches.
B.
never really thought of God as having a real existence.
C.
regarded religion as acceptable as long as it did not interfere.
D.
regarded religion as a way that he could live a spiritual life.
查看完整题目与答案
相关题目：
【多选题】1980年纪念陈垣诞辰结集的文集分别是
A.
陈垣校长诞辰百年纪念文集
B.
纪念陈垣诞辰一百周年史学论文集
C.
励耘书屋问学记
D.
其他
查看完整题目与答案
【判断题】为了防止直接触及带电体，通常采用漏电保护器、保护接地或接零等技术措施。
A.
正确
B.
错误
查看完整题目与答案
【简答题】阅读理解。 School education is very important and useful. The students both learn knowledge and get an education. Yet, no one can learn everything from school. The scientists (科学家) , such as Edison, Newton...
查看完整题目与答案
【单选题】燃烧时有大蒜样臭气的是
A.
信石
B.
赭石
C.
石膏
D.
硫黄
E.
雄黄
查看完整题目与答案
【简答题】Today, no one thinks of Bill Gates as a failed entrepreneur or a college dropout yet. Both of these things are true of Gates, American richest man and the pioneering genius who leads the computer soft...
查看完整题目与答案
【简答题】主要知识点: 1、背景图的插入与调整; 2、控制点曲线与内差点曲线的转换; 3、直线挤出,注意曲线的组合; 4、旋转阵列复制; 5、投影曲线
查看完整题目与答案
【简答题】阅读理解 School education is very important and useful. The students both learn  knowledge and get an education. Yet,no one can learn everything from school. The scientists, such as Edison, Newton, Galile...
查看完整题目与答案
【多选题】彩陶分布很广，在黄河上游有河南、河北、山西、陕西等地的(    )，黄河下游有(    )。
A.
仰韶文化    
B.
大汶口文化  
C.
河姆渡文化  
D.
屈家岭文化
查看完整题目与答案
【单选题】相对论主要是由谁创立的?
A.
爱因斯坦
B.
门捷列夫
C.
法拉第
D.
祖冲之
查看完整题目与答案
【单选题】I thought of God as a strangely emotional being. He was powerful He was forgiving yet obdurate, full of warmth and affection. Both His wrath and affection were fitful, they came and they went, and I c...
A.
had been born in natural surroundings with banks and churches.
B.
never really thought of God as having a real existence.
C.
regarded religion as acceptable as long as it did not interfere.
D.
regarded religion as a way that he could live a spiritual life.
查看完整题目与答案