如何防止重复输入 [英] How to prevent duplicate entry

问题描述

我有一个使用链接到访问数据库创建的用户表单。我有一个名为PV Numbers的列标题。我想知道如何阻止用户复制PV号码。



我尝试过：



我目前使用的代码是GBCPVRBindingSource.AddNew

i have a user-form created using linked to an access database. i have a column header named "PV Numbers". i would like to know how i can prevent users from duplicating the PV Numbers.

What I have tried:

The code am currently using is "GBCPVRBindingSource.AddNew"

推荐答案

数据库中的每个表必须具有主要密钥 [< a href =https://support.office.com/en-gb/article/Create-or-remove-a-primary-key-07b4a84b-0063-4d56-8b00-65f2975e4379#bm1\"target =_ blanktitle =新窗口> ^ ]这就是你要找的。

了解更多： SQL PRIMARY KEY约束 [ ^ ]

Every table in a database must have a primary key[^] and that is what you are looking for.
Learn more: SQL PRIMARY KEY Constraint[^]

正如彼得所说，主键就是这样。

你需要学习更好的SQL。

SQL教程 [ ^ ]

W3Schools在线网络教程 [ ^ ]

As Peter said, "Primary key" is the way.
You need to learn better SQL.
SQL Tutorial[^]
W3Schools Online Web Tutorials[^]

这篇关于如何防止重复输入的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！