blocks|key|1935542|text|是的，您可以在序列化程序的.validate()方法中这样做。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1935543|def+validate(self,+attrs):
++++try:
++++++++Model.objects.get(field1=attrs['field1'],+field2=attrs['field2'])
++++except+Model.DoesNotExist:
++++++++pass
++++else:
++++++++raise+serializers.ValidationError('field1+with+field2+already+exists')

++++return+attrs|code-block|syntax|javascript|1935544|在模型中设置的唯一约束用于创建数据库约束，而不是验证。|1935545|entityMap^0|D|B|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Yes, you can do it in the <code>.validate()</code> method of the serializer.

<pre class="lang-py prettyprint-override"><code>def validate(self, attrs):
 try:
 Model.objects.get(field1=attrs['field1'], field2=attrs['field2'])
 except Model.DoesNotExist:
 pass
 else:
 raise serializers.ValidationError('field1 with field2 already exists')

 return attrs
</code></pre>

The unique constraint that you set in your model is for creating database constraints, not for validating.

blocks|key|1655947|text|不幸的是，Andreas的回答并不完全，因为它在更新的情况下是行不通的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1655948|相反，您可能需要更像这样的东西：|1655949|def+validate(self,+attrs):
++++field1+=+attrs.get('field1',+self.object.field1)
++++field2+=+attrs.get('field2',+self.object.field2)

++++try:
++++++++obj+=+Model.objects.get(field1=field1,+field2=field2)
++++except+StateWithholdingForm.DoesNotExist:
++++++++return+attrs
++++if+self.object+and+obj.id+==+self.object.id:
++++++++return+attrs
++++else:
++++++++raise+serializers.ValidationError('field1+with+field2+already+exists')|code-block|syntax|javascript|1655950|这将适用于PUT、PATCH和POST。|1655951|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Unfortunately, Andreas's answer is not quite complete, as it will not work in the case of an update.

Instead, you would want something more like:

<pre><code>def validate(self, attrs):
 field1 = attrs.get('field1', self.object.field1)
 field2 = attrs.get('field2', self.object.field2)

 try:
 obj = Model.objects.get(field1=field1, field2=field2)
 except StateWithholdingForm.DoesNotExist:
 return attrs
 if self.object and obj.id == self.object.id:
 return attrs
 else:
 raise serializers.ValidationError('field1 with field2 already exists')
</code></pre>

This will work for PUT, PATCH, and POST.

blocks|key|1935577|text|ModelSerializer类具有此功能内建(至少在djangorestframework>=3.0.0中是如此)，但是如果您使用的是不包含所有受unique_together约束影响的字段的serializer，则在保存违反该约束的实例时将得到一个IntegrityError。例如，使用以下模型：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1935578|class+Foo(models.Model):
++++class+Meta:
++++++++unique_together+=+('foo_a',+'foo_b')

++++a+=+models.TextField(blank=True)
++++b+=+models.TextField(blank=True)
++++foo_a+=+models.IntegerField()
++++foo_b+=+models.IntegerField(default=2)|code-block|syntax|javascript|1935579|以及以下序列化程序和ViewSet：|1935580|class+FooSerializer(serializers.ModelSerializer):
++++class+Meta:
++++++++model+=+models.Foo
++++++++fields+=+('a',+'b',+'foo_a')

class+FooViewSet(viewsets.ModelViewSet):
++++queryset+=+models.Foo.objects.all()
++++serializer_class+=+FooSerializer


routes+=+routers.DefaultRouter()
routes.register(r'foo',+FooViewSet)|1935581|如果您试图保存两个具有相同foo_a和foo_b集的实例，您将得到一个IntegrityError。但是，如果我们像这样修改序列化程序：|1935582|class+FooSerializer(serializers.ModelSerializer):
++++class+Meta:
++++++++model+=+models.Foo
++++++++fields+=+('a',+'b',+'foo_a',+'foo_b')|1935583|然后，您将得到一个正确的HTTP+400+BAD+REQUEST状态代码，以及响应正文中相应的JSON描述性消息：|1935584|HTTP+400+BAD+REQUEST
Content-Type:+application/json
Vary:+Accept
Allow:+GET,+POST,+HEAD,+OPTIONS

{
++++"non_field_errors":+[
++++++++"The+fields+foo_a,+foo_b+must+make+a+unique+set."
++++]
}|1935585|我希望这会对你有所帮助，即使这是一个老问题;-)|1935586|entityMap^0|R|Q|22|F|2P|A|3I|E|0|0|0|0|D|5|J|5|Z|E|0|0|C|K|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1B|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1K|8|@$9|1L|A|1M|B|C]]|D|@]|E|$]]|$1|U|3|V|5|H|7|1N|8|@]|D|@]|E|$I|J]]|$1|W|3|X|5|6|7|1O|8|@]|D|@]|E|$]]|$1|Y|3|-4|5|6|7|1P|8|@]|D|@]|E|$]]]|Z|$]]

The ModelSerializer class has this functionality build-in, at least in <code>djangorestframework&gt;=3.0.0</code>, however if you are using a <code>serializer</code> which doesn't include all of the fields which are affected by your <code>unique_together</code>constrain, then you'll get an <code>IntegrityError</code> when saving an instance which violates it. For example, using the following model:

<pre><code>class Foo(models.Model):
 class Meta:
 unique_together = ('foo_a', 'foo_b')

 a = models.TextField(blank=True)
 b = models.TextField(blank=True)
 foo_a = models.IntegerField()
 foo_b = models.IntegerField(default=2)
</code></pre>

and the following serializer and ViewSet:

<pre><code>class FooSerializer(serializers.ModelSerializer):
 class Meta:
 model = models.Foo
 fields = ('a', 'b', 'foo_a')

class FooViewSet(viewsets.ModelViewSet):
 queryset = models.Foo.objects.all()
 serializer_class = FooSerializer


routes = routers.DefaultRouter()
routes.register(r'foo', FooViewSet)
</code></pre>

if you try to save two instances with the same <code>foo_a</code> and <code>foo_b</code> set, you'll get an <code>IntegrityError</code>. However, if we modify the serializer like this:

<pre><code>class FooSerializer(serializers.ModelSerializer):
 class Meta:
 model = models.Foo
 fields = ('a', 'b', 'foo_a', 'foo_b')
</code></pre>

you'll then get a proper <code>HTTP 400 BAD REQUEST</code> status code, and the corresponding JSON descriptive message in the response body:

<pre><code>HTTP 400 BAD REQUEST
Content-Type: application/json
Vary: Accept
Allow: GET, POST, HEAD, OPTIONS

{
 "non_field_errors": [
 "The fields foo_a, foo_b must make a unique set."
 ]
}
</code></pre>

I hope this to result helpful for you, even when this is a somewhat old-posted question ;-)

blocks|key|936035|text|我需要这个来覆盖默认消息。由这解决。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|936036|from+django.utils.translation+import+ugettext_lazy+as+_
from+rest_framework+import+serializers


class+SomeSerializer(serializers.ModelSerializer):
++"""
++Demostrating+How+to+Override+DRF+UniqueTogetherValidator+Message
++"""

++++class+Meta:
++++++++model+=+Some
++++++++validators+=+[
++++++++++++serializers.UniqueTogetherValidator(
++++++++++++++++queryset=model.objects.all(),
++++++++++++++++fields=('field1',+'field2'),
++++++++++++++++message=_("Some+custom+message.")
++++++++++++)
++++++++]|code-block|syntax|javascript|936037|Similarly+you+can+specify+fields|style|CODE|936038|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/vaibhav-jain/91f49e8252ad4860b419868f704bbcf7^0|E|1|0|0|0|0|W|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@$A|10|B|11|K|L]]|9|@]|C|$]]|$1|M|3|-4|5|6|7|12|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

I Needed this to override default message. Solved it by <a href="https://gist.github.com/vaibhav-jain/91f49e8252ad4860b419868f704bbcf7" rel="noreferrer">this</a>.

<pre><code>from django.utils.translation import ugettext_lazy as _
from rest_framework import serializers


class SomeSerializer(serializers.ModelSerializer):
 """
 Demostrating How to Override DRF UniqueTogetherValidator Message
 """

 class Meta:
 model = Some
 validators = [
 serializers.UniqueTogetherValidator(
 queryset=model.objects.all(),
 fields=('field1', 'field2'),
 message=_("Some custom message.")
 )
 ]
</code></pre>

<code>Similarly you can specify fields</code>

blocks|key|936079|text|这有点愚蠢，除了我以外的任何人都不太可能犯这个错误，但是我把相同的模型放在两个序列化器类中，结果我遇到了这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|936080|希望我的错误能帮助到别人！|936081|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Well this is kinda stupid and it's very unlikely that anyone but me would make this mistake, but I had put the same model in two serializers class, as a consequence I had this problem

Hope my mistake help someone!

blocks|key|1935662|text|有同样的问题，从这个答案https://stackoverflow.com/a/26027788/6473175，我能够让它工作，但不得不使用self.instance而不是self.object。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1935663|def+validate(self,+data):
++++field1+=+data.get('field1',None)
++++field2+=+data.get('field2',None)

++++try:
++++++++obj+=+self.Meta.model.objects.get(field1=field1,+field2=field2)
++++except+self.Meta.model.DoesNotExist:
++++++++return+data
++++if+self.instance+and+obj.id+==+self.instance.id:
++++++++return+data
++++else:
++++++++raise+serializers.ValidationError('custom+error+message')|code-block|syntax|javascript|1935664|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/26027788/6473175^0|1Z|D|2F|B|C|18|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Had the same problem and from this answer <a href="https://stackoverflow.com/a/26027788/6473175">https://stackoverflow.com/a/26027788/6473175</a> I was able to get it to work but had to use <code>self.instance</code> instead of <code>self.object</code>.

<pre><code>def validate(self, data):
 field1 = data.get('field1',None)
 field2 = data.get('field2',None)

 try:
 obj = self.Meta.model.objects.get(field1=field1, field2=field2)
 except self.Meta.model.DoesNotExist:
 return data
 if self.instance and obj.id == self.instance.id:
 return data
 else:
 raise serializers.ValidationError('custom error message')
</code></pre>

Having issues with a <code>serializer.is_valid()</code> returning <code>True</code> if the serializer instance fails a <code>unique_together</code> constraint on the model side.

Is there a way for me to specify in the serializer to enforce a <code>unique_together</code> constraint?

Django REST Framework: Unique_together validation on Serializers

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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如果序列化程序实例在模型端失败了一个serializer.is_valid()约束，则返回True的unique_together会出现问题。是否有一种方法可以在序列化程序中指定以强制执行unique_together约束？

问Django REST框架:序列化程序上的Unique_together验证
EN

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问Django REST框架:序列化程序上的Unique_together验证EN