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帮助我的SQL之友名单
原标题:Help with MySQL Friends List

我正在做一个安乐器,它将使用朋友名单。 就我所知,你可以把一阵列放在我的我的我的我的我的我的我的我的桌子上,因此,我似乎不得不从我的“用户”桌上单独开一个桌,称之为“之友”。 本表只有“友好”1和“友好”2。

我的问题是存放这一表格的首选方式。 我可以使用我的“用户”表上的用户Name领域(显示)储存这些用户,或者我可以使用我的“用户”表上的用户信息数据库(integer)。 使用该表会缩小,因为小户户的占用空间大于铺设面积,但与此同时,我主要利用用户Name领域获得这一数据(因此,我不得不询问用户表,以从用户表中获取用户信息数据库)。

在MySQL表格中选择哪种方法? 利用用户名称,我无需从用户表中找到用户信息数据库,或将表格作为两个分类,并询问如何从用户Name中找到该数据? 感谢。

问题回答

储存2个用户 用户表中的ID钥匙。

Let s say that you change a name of a contact from "Guy from bar" to "Mr. McMoneypants". If this contact was a friend, it will still show up as "Guy from bar" even after the change.

要求将数据保存在多个地方。

The preferred method is to use the UserID from the Users table in the Friends table as a way to reference that user. That way, as Phillip says, the User can change their name and you only have to change it in one place. Plus, as you say, your Friends table will take up less space with a numeric column as compared to a string column.

关于<代码>(因此,我不得不询问用户表,以便用户信息数据库从用户表中获取),以下询问并不过于繁琐:

SELECT FriendName
FROM Users Natural Left Join Friends
WHERE UserName =  Ralph ;

As far as your query is concerned, you never had to deal with the UserID column. That s not that much harder than your method:

SELECT FriendName
FROM Friends
WHERE UserName =  Ralph ;




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