视图不能单独存在，它必须依赖于( )。
A．视图
B．数据库
C．查询
D．数据表
参考答案：B
解析： 视图是一个定制的虚拟逻辑表，视图中值存放相应的数据逻辑关系，并不保存表的记录内容，但可以在视图中更新该表记录的值，然后将更新记录返回到源表。所以视图只是操作表的一种手段，通过视图可以查询表，也可以更新表。视图是数据库中的一个特有功能，只有在包含视图的数据库打开时，才能使用视图。
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| When I was a little girl, every Sunday my family of six would put on our best clothes and go to Sunday School and then church. The 1 in elementary school would all meet together to sing songs, and then later divide into groups based 2 their ages. One Easter Sunday, all the kids 3 with big 4 about what the Easter Bunny (复活节兔子) had brought. 5 all of the kids shared their stories with 6 , one young boy, whom I should call Bobby, sat 7 . One of the teachers, noticing this, said to him, "And what did the Easter Bunny 8 you?" He replied, "My mum 9 the door by accident so the Easter Bunny couldn't get 10 because he hadn't got a key." This sounded like a 11 idea to all of us kids, so we kept on going with the stories. My mom knew the true story, 12 . Bobby's mom was a single parent, and she suspected (怀疑) that they just couldn't 13 the Easter Bunny. After Sunday School was over, everyone went off to 14 . But my mom announced that we were going home 15 . At home, she explained that to make Bobby feel 16 , we were going to pretend to be the Easter Bunny, make a basket of our candies for him and 17 it at church. We all donated some to the basket, and 18 back to church. There, mom hung the basket over the hanger (挂钩) and attached a(n) 19 : Dear Bobby, I'm sorry I 20 your house last night. Happy Easter! Love, The Easter Bunny | ||||
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