如何增加和减少Access中的项目数 [英] How to increase and decease number of item in Access

问题描述

大家好，我在开发图书管理系统时正在处理Access数据库2007，我希望借书时这会影响该书的副本数量。同样会影响所有书籍数量，以及那么如果有人以相同的方式返回增加书籍数量的书，我希望如此。

基本上我想知道如何设置这样的场景，当书籍被退回时会有所增加，当从图书馆借来时会减少。

请我需要你的帮助来处理这个问题。



我想知道如何在不使用查询表的情况下计算表中的overdue_days，甚至可以计算乘以列的结果并提供结果那张桌子。



我将很感激你的支持，上帝会为此祝福你。

好​​的，感谢所有愿意花时间帮助我的人。

Hello guys, I'm dealing with Access database 2007 when developing a library management system, I would like that when the book is borrowed that's affect the number of copies of that book .the same affect the all number of books, and then I would like that if someone return back the book that increase the number of book in the same way.
Basically I want to know how I can set that scenario where there is increase of the books when are returned back and decrease when they are borrowed from library.
Please I need your help to handle that.

I would like to know how if it can be possible to calculate overdue_days in table without using query table and even calculation that make multiplication of to column and provide the result in that same table.

I will be grateful to have your support and God will bless you indeed for that.
ok thank you in advance of everyone who will take his or her time in helping me.

推荐答案

这是一个功课，我们不提供解决方案...设置家庭作业，以便你可以从中学习。



你需要活动来处理借书和归还 - 这些事件需要更新可用副本的数量，或者将每个副本标记为输入/输出，具体取决于您决定设计数据库的方式。



您可以在数据库中存储过期天数，但是您必须有一个定期更新该计算的事件。在查询运行时解决问题有什么问题？



谷歌有很多这方面的例子 - 但要注意，你的导师很可能也知道如何谷歌。



有一个去，通过课程或教程，你并不像你想象的那么难。



但是如果你自己尝试过这个代码后遇到特定的问题，请回来。





以下是一些让你入门的链接

http://www.sourcecodester.com/tutorials/microsoft-access/create-a-library-system-database.html [ ^ ]



http://www.google.co.uk/url?sa=t&rct=j&q=library+management+system+access+database&源=纸幅放大器; CD = 3及CAD = RJA&安培; VED = 0CEsQFjAC&安培; URL = HTTP％3A％2F％2Fwww.youtube.com％2Fwatch％3Fv％3D5-KXGKIoFIM&安培; EI = jss5UpauGcWk4ATaoIHYDQ&安培; USG = AFQjCNH__RyUSSHbT08RcOXn4wIusk9dKw&安培; BVM = BV。 52288139，d.bGE [ ^ ]

This smacks of homework, which we do not supply solutions to ... homework is set so that you can learn from it.

You will need events to handle the borrowing of a book and its return - these events will need to update the number of available copies, or mark each copy as in/out depending on how you decide to design your database.

You could have the number of overdue days stored on your database, but you are going to have to have an event that would update that calculation on a regular basis. What's wrong with working it out at the time that the query is run?

There are plenty of examples of this sort of thing in Google - but beware, your tutor probably knows how to google too.

Have a go, work your way through the lesson or tutorial, it's not as hard as you think.

But do come back if you have a specific problem with your code once you've tried this yourself.


Here are some links to get you started
http://www.sourcecodester.com/tutorials/microsoft-access/create-a-library-system-database.html[^]

http://www.google.co.uk/url?sa=t&rct=j&q=library+management+system+access+database&source=web&cd=3&cad=rja&ved=0CEsQFjAC&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D5-KXGKIoFIM&ei=jss5UpauGcWk4ATaoIHYDQ&usg=AFQjCNH__RyUSSHbT08RcOXn4wIusk9dKw&bvm=bv.52288139,d.bGE[^]

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