我如何在表之间建立这种关系 [英] How I can do this relation between tables
问题描述
我必须在桌子上访问
表不，1内容
i have to table in access
table No,1 Content
Names , Students grade
qassem . 300
noor . 280
表不，2个内容
table No,2 content
schoolsName , Students grade
aaaaaaa . 290
bbbbbbb . 270
ccccccc . 250
i希望在C＃2012视觉工作室中将这些表格链接到我们
当学生的最终成绩打开所有学校时
之后，每个学生按照给他的成绩打开他的选择
我无法链接到他们
谢谢
i am Egyptian
我的一些英语知识
i want to link those table with us in C# 2012 visual studio
When the students' final grades open them all schools
After that each student opens his choices by grade given to him
I can not link to them
thank you
i am Egyptian
A few my knowledge in English
推荐答案
您需要主表中的主键和详细信息表中的外键，然后从SQL Server管理工作室中为此2个键和VB .Net进行连接你使用2个bindingsource对象进行相同的连接。
You need a primary key in the master table and a Foreign key in the detail table, then from SQL Server managment studio you do the join for this 2 keys and in VB .Net you do the same same join with 2 bindingsource objects.
问题是为了在表之间建立关系，它们需要有一个共同的值。它就像一个MP3：它有一个标题，但它也有一个音乐家（或乐队）制作它。所以你可以有两张桌子：
艺术家：
The problem is that in order to establish a relationship between tables, they need to have a common value. It's like an MP3: it has a title, but it also has a musician (or band) that made it. So you could have two tables:
Artists:
ID ArtistName
1 Lana Del Ray
2 Coldplay
...因为一个乐队或艺术家可能会产生多个曲目，所以将它们存储在自己的表中是有意义的 - 否则你将复制一个乐队名称，并且再一次。
和一张曲目表：
曲目：
Because a band or artist is likely to produce more than one track, it makes sense to store them in their own table - otherwise you will be duplicating teh smae band name over, and over again.
And a Tracks table:
Tracks:
ID ArtistID TrackName
1 1 Gods and Monsters
2 1 Ride
3 2 Paradise
4 2 Fix You
...
你可以在Tracks.ArtistID和Artists.ID列上的曲目和艺术家之间建立外键关系。
这可以让你获取相关信息：
And you can establish a foreign key relationship between the Tracks and Artists on the Tracks.ArtistID and Artists.ID columns.
That lets you fetch related information:
SELECT a.ArtistName, t.TrackName
FROM Tracks t
JOIN Artists a ON t.ArtistID=a.ID然后返回：
And that returns you:
Gods and Monsters Lana Del Ray
Ride Lana Del Ray
Paradise Coldplay
Fix You Coldplay
...但如果你没有连结专栏 ArtistsID然后没有办法连接两张桌子。
但是......在你的例子中，你不想要链接根本没有。
您要做的是检查每个学生成绩与学校将接受的最低价值，并显示学生可以去哪些学校。
那是只是一个简单的SQL查询：
But if you don't have the "linking column" of the ArtistsID then there isn't a way to "connect" the two tables.
But...in your example, you don't want a "link" at all.
What you want to do is check each student grade against the minimum value the schools will accept and show which schools the student can go to.
That's just a simple SQL query:
SELECT Students.StudentName, Schools.SchoolName FROM Students, Schools
WHERE Students.Grade >= Schools.MinGrade这给出了你：
And that gives you:
StudentName SchoolName
qassem aaaaaaa
qassem bbbbbbb
qassem ccccccc
noor bbbbbbb
noor ccccccc
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