擅长:python、mysql、java
<p>您可以在ForeignKeyFields和ManyToManyFields上使用<a href="https://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.models.ForeignKey.limit_choices_to" rel="nofollow">limit_choices_to</a>特性。你的模型.py文件可能如下所示:</p>
<pre><code>class PersonArchive(models.Model):
tags_field = models.ManyToManyField(Tag, related_name="people_archives", limit_choices_to={'message_archives__isnull': True})
class MessageArchive(models.Model):
tags_field = models.ManyToManyField(Tag, related_name="message_archives", limit_choices_to={'people_archives__isnull': True})
</code></pre>