停止在Free表中输入空值 [英] Stop to enter null values in Free table

问题描述

亲爱的所有 

Dear all 

请在下面找到两个截图并帮我解决这个问题

Please find below two screen-shot and help me to solve out this problem

当我跑步时我的 凭证输入程序有时候这种类型的数据会在数据库中添加如何阻止他们在数据库中添加  

when i have run my  voucher entry program some time this type of data is add in database how to stop them to add in database  

推荐答案

最后一个截图显示它不是NULL而是空字符串。

The last screenshot shows it's not NULL but empty string.

每当您希望记录的字段不为空时，您的输入控件不应允许空值。这应该是清楚的，那么你的问题到底是什么？每当您首先保存记录时，检查此值不为空。理想情况下，只允许用户
从列表框或下拉组合框中选择一个有效值，如果该值为空，请关注该控件，发出警告声或高亮控件，以便用户知道这是丢失或错误的，很多这样做的方法。

Whenever you want a field of a record to not be empty your input control shouldn't allow an empty value. That should be clear, so what really is your question? Whenever you save a record first check this value is not empty. Ideally only allow the user to pick a valid value from a listbox or dropdown combobox and if the value is empty, focus that control, play a warning sound or highlicght the control so the user knows this is missing or wrong, Many ways to do that.

在DBC的表格部分中，您可以定义字段规则。在免费的DBF中，您必须自己检查表单中的那些。

In a table part of a DBC you can define field rules. In a free DBF you have to check those in your forms yourself.

记录安全例程应该调用一个检查例程，并且只保存符合良好记录规则的记录。

A record safe routine should call a check routine and only save records fulfilling the rules of a good record.

再见，奥拉夫。

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