擅长:python、mysql、java
<p>看看<a href="https://stackoverflow.com/questions/6940499/how-can-you-create-a-non-empty-charfield-in-django#47337947">this answer</a>:</p>
<pre><code>class ClientDebt(models.Model):
client_id = models.CharField(max_length=255, blank=False, default=None)
...
</code></pre>
<ul>
<li><code>blank</code>将阻止在模型中提供空字符串</li>
<li><code>default=None</code>在使用类似<code>group = Group()</code>的东西时,会将name设置为None,从而在调用<code>save</code>时引发异常</li>
</ul>
<p>或者,您可能想看看<a href="https://docs.djangoproject.com/en/2.2/ref/validators/#minlengthvalidator" rel="nofollow noreferrer">MinLengthValidator</a>。你知道吗</p>