我知道现在可以做到！ [英] I know it can be done now!

问题描述

在业余时间，我一直在尝试为我的小组中的

员工创建一个Access数据库超过一个月。当我在访问圣经中读到$ 2 $
表中的主键之间的关系必须是1：1时，我感到很惊讶！我无法想象为什么存在这种限制！

我甚至在这里问过，但没有得到满意的答案。我的情况是

我有一份员工列表，每个员工都有一个Employee

ID的主键，以及一个计算机列表，每个计算机都有一个主键是Computer ID 。

但是有些电脑是笔记本电脑，并借给台式电脑借给人们b / b
。所以我需要在

员工ID和计算机ID之间建立一对多的关系。 Access 2000圣经说我不能这样做

如果它们都是他们表中的主键，那就是它们。

今天，我加载了示例文件这本书附带的。猜猜是什么？

两张桌子之间有一段关系，在他们的主要
键之间，就是1：很多！我知道完全禁止这样的关系是没有意义的。

所以现在我想知道，我该如何建立这种关系？我注意到

示例文件中的一个表有多个主键。我不知道怎么可能，但我想你可以在

Access中做到这一点，所以它没有任何意义。那部分诀窍

在主键之间创建1：很多关系？如果是这样的话，

其余部分是什么？

感谢您的帮助！

Have been trying, in my spare time, to create an Access db for the
employees in my group for over a month. It surprised me when I read in
the Access Bible that a relationship between the Primary Keys in 2
tables had to be 1:1! I couldn''t imagine why this restriction existed!
I even asked here, but didn''t get satisfactory answers. My situation is
that I have a list of employees, each having a primary key of Employee
ID, and a list of computers, each having a primary key of Computer ID.
But some of the computers are laptops, and get loaned out to people
with desktops. So I need to create a one to many relationship between
employee ID and computer ID. The Access 2000 Bible says I can''t do it
if they are both the primary key in their table, which they are.
Today, I loaded the sample files that come with the book. Guess what?
There is a relationship between 2 of the tables, between their primary
keys, that is 1:many! I knew it didn''t make sense to prohibit such a
relatsionship entirely.
So now I want to know, how do I create such a relationship? I noticed
that the one table in the sample file had multiple primary keys. I
don''t understand how that''s possible, but I guess you can do it in
Access, so it doesn''t have to make any sense. Is that part of the trick
to create a 1:many relationship between primary keys? If so, what is
the rest of it?
Thanks for your help!

推荐答案

davegb< da **** @ safebrowse.com>写道：

davegb <da****@safebrowse.com> wrote:

在业余时间，我一直在尝试为我的团队中的
员工创建一个Access数据库超过一个月。当我在访问圣经中读到2
表中的主键之间的关系必须是1：1时，我感到很惊讶！


你确定吗？或者他们是说你不能拥有多对多的b
关系？

我无法想象为什么存在这种限制！


它没有。

我甚至在这里问过，但没有得到满意的答案。我的情况
是我有一份员工清单，每个员工都有一个
员工ID的主键，以及一个计算机列表，每个计算机都有一个主键为
计算机ID。但是有些计算机是笔记本电脑，并且可以借给台式机的人借出。所以我需要在员工ID和计算机ID之间创建一对多的关系。 Access 2000
圣经说，如果它们都是他们
表中的主键，我就不能这样做。


tblEmployee - < tblComputers


您当然可以在

tblEmployee.EmployeeID和tblComputers.EmployeeID之间建立一对多的关系。这允许每个

员工与许多计算机相关联，但每台计算机只能与一名员工关联
。


注意：


- 如果表中已有数据，则可能会阻止创建关系

（例如，如果你有一个tblComputers.EmployeeID值，那么

在tblEmployees中不存在。）


- 你没有关联主键。您将
tblEmployee（EmployeeID）中的主键与tblComputers（EmployeeID）中的字段相关联。

今天，我加载了来自
的示例文件书。你猜怎么着？
表之间，主键之间有一个关系，就是1：很多！我知道完全禁止这种关系是没有意义的。
所以现在我想知道，我该如何建立这种关系呢？我注意到示例文件中的一个表有多个主键。


不是。你不可能有多个主键，但是你可以有其他

键不是主键。

我不知道怎么做这是可能的，但我想你可以在访问中做到这一点，所以它没有任何意义。是否可以在主键之间创建1：多关系？如果是这样的话，
剩下的是什么？
感谢您的帮助！

Have been trying, in my spare time, to create an Access db for the
employees in my group for over a month. It surprised me when I read in
the Access Bible that a relationship between the Primary Keys in 2
tables had to be 1:1!
You sure? Or were they saying that you can''t have many-to-many
relationships?
I couldn''t imagine why this restriction existed!
It doesn''t.
I even asked here, but didn''t get satisfactory answers. My situation
is that I have a list of employees, each having a primary key of
Employee ID, and a list of computers, each having a primary key of
Computer ID. But some of the computers are laptops, and get loaned
out to people with desktops. So I need to create a one to many
relationship between employee ID and computer ID. The Access 2000
Bible says I can''t do it if they are both the primary key in their
table, which they are.
tblEmployee -< tblComputers

You can certainly create a one-to-many relationship between
tblEmployee.EmployeeID and tblComputers.EmployeeID. This allows each
employee to be associated with many computers, but each computer can
only be associated with one employee.

Note:

- If you already have data in the table it may prevent a relationship
being created (eg. if you have an tblComputers.EmployeeID value that
doesn''t exist in tblEmployees).

- You aren''t relating the primary keys. Your relating the primary key in
tblEmployee (EmployeeID) to a field in tblComputers (EmployeeID).
Today, I loaded the sample files that come
with the book. Guess what? There is a relationship between 2 of the
tables, between their primary keys, that is 1:many! I knew it didn''t
make sense to prohibit such a relatsionship entirely.
So now I want to know, how do I create such a relationship? I noticed
that the one table in the sample file had multiple primary keys.
It isn''t. You can''t have mutliple primary keys, but you can have other
keys that aren''t primary.
I
don''t understand how that''s possible, but I guess you can do it in
Access, so it doesn''t have to make any sense. Is that part of the
trick to create a 1:many relationship between primary keys? If so,
what is the rest of it?
Thanks for your help!

听起来你需要更多关于数据库理论的研究： 0

-

问候，


布拉德利


基督徒的回应
http://www.pastornet.net.au/response

听起来你需要创建一个第三个表来保存这些字段

外键EmployeeID，ComputerID，（可选 - 解释性文本 -

解释链接的原因）。现在将您的EmployeeID从

员工表（主键）链接到第3表的EmployeeID（1-many）和

将ComputerID从计算机表（主键）链接到ComputerID of第3页

表（1-many）。除此之外，在第3个表格中，使用

EmployeeID和ComputerID组合一个唯一键。实际上，第3张
表是连接表或连接表。


HTH


Steve。

Sounds like you need to create a 3rd table which holds these fields as
foreign keys EmployeeID, ComputerID, (optional - explanatory text -
explaining reason for the link). Now link your EmployeeID from
Employee table (primary key) to EmployeeID of 3rd table (1-many) AND
link ComputerID from Computer table (primary key) to ComputerID of 3rd
table (1-many). Further to this, within the 3rd table, make
EmployeeID and ComputerID a combine unique key. Effectively the 3rd
table is a linking table or joining table.

HTH

Steve.

su ********* @ gmail.com 写道：

听起来你需要创建一个第三个表，它将这些字段保存为外键EmployeeID，ComputerID，（可选 - 解释性文本 -
解释链接的原因）。现在将您的EmployeeID从
员工表（主键）链接到第3表的EmployeeID（1-many）并将计算机表（主键）中的ComputerID链接到3rd表的ComputerID（1 -许多）。此外，在第3个表中，使EmployeeID和ComputerID成为组合唯一键。实际上，第3张表是连接表或连接表。

HTH

史蒂夫。

Sounds like you need to create a 3rd table which holds these fields as
foreign keys EmployeeID, ComputerID, (optional - explanatory text -
explaining reason for the link). Now link your EmployeeID from
Employee table (primary key) to EmployeeID of 3rd table (1-many) AND
link ComputerID from Computer table (primary key) to ComputerID of 3rd
table (1-many). Further to this, within the 3rd table, make
EmployeeID and ComputerID a combine unique key. Effectively the 3rd
table is a linking table or joining table.

HTH

Steve.

这是怎么回事实现多对多关系。我不认为

是必要的，因为计算机一次只能与一个

员工相关联（这就是我如何理解他是什么无论如何说:)。

因此你只需要将EmployeeID添加到计算机表中并且

有一个（员工）对多（计算机）关系。

-

问候，


布拉德利


基督徒的回应
http://www.pastornet.net.au/response

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