在关系模型中,把数据看成是二维表,每一个二维表称为一个()。
参考答案:关系
解析:
在 Visual FoxPro 中,一个“表”就是一个关系。一个关系的逻辑结构就是一张二维表。
Number the sentences. (为下面对话排序)
( )They are three dollars a kilo.
( )Thanks and see you later.
( )Sure. Here you are. Three dollars, please.
( )Thanks. Here is three dollars.
( )How much are the tomatoes?
( )May I have a kilo, please?
试析幼儿不良品德形成的原因及其纠正战略。