blocks|key|3326560|text|有两种方法可以做到这一点。一种是使用表单验证，永远不让用户输入任何超过50的数字。Form+validation+docs。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3326561|如果流程中没有用户，或者您没有使用表单输入数据，则必须覆盖模型的save方法以抛出异常或限制进入字段的数据。|style|CODE|3326562|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.djangoproject.com/en/dev/ref/forms/validation/^0|15|K|0|0|W|4|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@$A|U|B|V|F|G]]|9|@]|C|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|C|$]]]|I|$J|$5|K|L|M|C|$N|O]]]]

There are two ways to do this. One is to use form validation to never let any number over 50 be entered by a user. <a href="http://docs.djangoproject.com/en/dev/ref/forms/validation/" rel="noreferrer">Form validation docs</a>.

If there is no user involved in the process, or you're not using a form to enter data, then you'll have to override the model's <code>save</code> method to throw an exception or limit the data going into the field.

blocks|key|342891|text|您还可以创建自定义模型字段类型-请参阅http://docs.djangoproject.com/en/dev/howto/custom-model-fields/#howto-custom-model-fields|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|342892|在这种情况下，您可以“继承”内置的IntegerField并覆盖它的验证逻辑。|342893|我想得越多，我就意识到这对许多Django应用程序是多么有用。也许可以将IntegerRangeField类型作为补丁提交给Django开发人员，以便考虑添加到主干中。|342894|这对我很有效：|342895|from+django.db+import+models

class+IntegerRangeField(models.IntegerField):
++++def+__init__(self,+verbose_name=None,+name=None,+min_value=None,+max_value=None,+**kwargs):
++++++++self.min_value,+self.max_value+=+min_value,+max_value
++++++++models.IntegerField.__init__(self,+verbose_name,+name,+**kwargs)
++++def+formfield(self,+**kwargs):
++++++++defaults+=+{'min_value':+self.min_value,+'max_value':self.max_value}
++++++++defaults.update(kwargs)
++++++++return+super(IntegerRangeField,+self).formfield(**defaults)|code-block|syntax|javascript|342896|然后在您的模型类中，您将像这样使用它(field是您放置上述代码的模块)：|342897|size+=+fields.IntegerRangeField(min_value=1,+max_value=50)|342898|或者对于负值和正值的范围(如振荡器范围)：|342899|size+=+fields.IntegerRangeField(min_value=-100,+max_value=100)|342900|如果可以像下面这样用范围操作符调用它，那将是非常酷的：|342901|size+=+fields.IntegerRangeField(range(1,+50))|342902|但是，这将需要更多的代码，因为你可以指定一个“跳过”参数-+range(1，50，2)+-有趣的想法……|342903|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.djangoproject.com/en/dev/howto/custom-model-fields/#howto-custom-model-fields^0|J|2H|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|D|3|E|5|6|7|1E|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|1F|8|@]|9|@]|C|$]]|$1|H|3|I|5|6|7|1G|8|@]|9|@]|C|$]]|$1|J|3|K|5|L|7|1H|8|@]|9|@]|C|$M|N]]|$1|O|3|P|5|6|7|1I|8|@]|9|@]|C|$]]|$1|Q|3|R|5|L|7|1J|8|@]|9|@]|C|$M|N]]|$1|S|3|T|5|6|7|1K|8|@]|9|@]|C|$]]|$1|U|3|V|5|L|7|1L|8|@]|9|@]|C|$M|N]]|$1|W|3|X|5|6|7|1M|8|@]|9|@]|C|$]]|$1|Y|3|Z|5|L|7|1N|8|@]|9|@]|C|$M|N]]|$1|10|3|11|5|6|7|1O|8|@]|9|@]|C|$]]|$1|12|3|-4|5|6|7|1P|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]]]

You could also create a custom model field type - see <a href="http://docs.djangoproject.com/en/dev/howto/custom-model-fields/#howto-custom-model-fields" rel="noreferrer">http://docs.djangoproject.com/en/dev/howto/custom-model-fields/#howto-custom-model-fields</a>

In this case, you could 'inherit' from the built-in IntegerField and override its validation logic.

The more I think about this, I realize how useful this would be for many Django apps. Perhaps a IntegerRangeField type could be submitted as a patch for the Django devs to consider adding to trunk.

This is working for me:

<pre><code>from django.db import models

class IntegerRangeField(models.IntegerField):
 def __init__(self, verbose_name=None, name=None, min_value=None, max_value=None, **kwargs):
 self.min_value, self.max_value = min_value, max_value
 models.IntegerField.__init__(self, verbose_name, name, **kwargs)
 def formfield(self, **kwargs):
 defaults = {'min_value': self.min_value, 'max_value':self.max_value}
 defaults.update(kwargs)
 return super(IntegerRangeField, self).formfield(**defaults)
</code></pre>

Then in your model class, you would use it like this (field being the module where you put the above code):

<pre><code>size = fields.IntegerRangeField(min_value=1, max_value=50)
</code></pre>

OR for a range of negative and positive (like an oscillator range):

<pre><code>size = fields.IntegerRangeField(min_value=-100, max_value=100)
</code></pre>

What would be really cool is if it could be called with the range operator like this:

<pre><code>size = fields.IntegerRangeField(range(1, 50))
</code></pre>

But, that would require a lot more code since since you can specify a 'skip' parameter - range(1, 50, 2) - Interesting idea though...

blocks|key|345393|text|我也遇到了同样的问题，下面是我的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|345394|SCORE_CHOICES+=+zip(+range(1,n),+range(1,n)+)
score+=+models.IntegerField(choices=SCORE_CHOICES,+blank=True)|code-block|syntax|javascript|345395|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I had this very same problem; here was my solution:

<pre><code>SCORE_CHOICES = zip( range(1,n), range(1,n) )
score = models.IntegerField(choices=SCORE_CHOICES, blank=True)
</code></pre>

blocks|key|3326648|text|您可以使用Django's+built-in+validators-|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3326649|from+django.db.models+import+IntegerField,+Model
from+django.core.validators+import+MaxValueValidator,+MinValueValidator

class+CoolModelBro(Model):
++++limited_integer_field+=+IntegerField(
++++++++default=1,
++++++++validators=[
++++++++++++MaxValueValidator(100),
++++++++++++MinValueValidator(1)
++++++++]
+++++)|code-block|syntax|javascript|3326650|编辑：当直接操作模型时，请确保在保存模型之前调用模型full_clean方法，以便触发验证器。在使用ModelForm时，这不是必需的，因为表单将自动执行此操作。|style|BOLD|CODE|3326651|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.djangoproject.com/en/dev/ref/validators/#built-in-validators|1|https://docs.djangoproject.com/en/2.2/ref/models/instances/#django.db.models.Model.full_clean^0|5|S|0|0|0|0|2|1E|9|Q|A|1|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@$A|Y|B|Z|1|10]]|C|$]]|$1|D|3|E|5|F|7|11|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|12|8|@$A|13|B|14|K|L]|$A|15|B|16|K|M]]|9|@$A|17|B|18|1|19]]|C|$]]|$1|N|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]]|O|$P|$5|Q|R|S|C|$T|U]]|V|$5|Q|R|S|C|$T|W]]]]

You can use <a href="https://docs.djangoproject.com/en/dev/ref/validators/#built-in-validators" rel="noreferrer">Django's built-in validators</a>—

<pre><code>from django.db.models import IntegerField, Model
from django.core.validators import MaxValueValidator, MinValueValidator

class CoolModelBro(Model):
 limited_integer_field = IntegerField(
 default=1,
 validators=[
 MaxValueValidator(100),
 MinValueValidator(1)
 ]
 )
</code></pre>

Edit: When working directly with the model, make sure to call the model <a href="https://docs.djangoproject.com/en/2.2/ref/models/instances/#django.db.models.Model.full_clean" rel="noreferrer">full_clean</a> method before saving the model in order to trigger the validators. This is not required when using <code>ModelForm</code> since the forms will do that automatically.

blocks|key|3326653|text|from+django.db+import+models
from+django.core.validators+import+MinValueValidator,+MaxValueValidator

size+=+models.IntegerField(validators=[MinValueValidator(0),
+++++++++++++++++++++++++++++++++++++++MaxValueValidator(5)])|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3326654|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>from django.db import models
from django.core.validators import MinValueValidator, MaxValueValidator

size = models.IntegerField(validators=[MinValueValidator(0),
 MaxValueValidator(5)])
</code></pre>

blocks|key|3113894|text|如果您想要一些额外的灵活性，并且不想更改您的模型字段，这里是最好的解决方案。只需添加此自定义验证器：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3113895|#Imports
from+django.core.exceptions+import+ValidationError++++++

class+validate_range_or_null(object):
++++compare+=+lambda+self,+a,+b,+c:+a+>+c+or+a+<+b
++++clean+=+lambda+self,+x:+x
++++message+=+('Ensure+this+value+is+between+%25(limit_min)s+and+%25(limit_max)s+(it+is+%25(show_value)s).')
++++code+=+'limit_value'

++++def+__init__(self,+limit_min,+limit_max):
++++++++self.limit_min+=+limit_min
++++++++self.limit_max+=+limit_max

++++def+__call__(self,+value):
++++++++cleaned+=+self.clean(value)
++++++++params+=+{'limit_min':+self.limit_min,+'limit_max':+self.limit_max,+'show_value':+cleaned}
++++++++if+value:++#+make+it+optional,+remove+it+to+make+required,+or+make+required+on+the+model
++++++++++++if+self.compare(cleaned,+self.limit_min,+self.limit_max):
++++++++++++++++raise+ValidationError(self.message,+code=self.code,+params=params)|code-block|syntax|javascript|3113896|它可以这样使用：|3113897|class+YourModel(models.Model):

++++....
++++no_dependents+=+models.PositiveSmallIntegerField("How+many+dependants?",+blank=True,+null=True,+default=0,+validators=[validate_range_or_null(1,100)])|3113898|两个参数分别是max和min，它允许为空。如果愿意，您可以通过删除标记为if的语句或将模型中的字段更改为blank=False、null=False来自定义验证器。这当然需要迁移。|3113899|注意:我必须添加验证器，因为Django不会验证PositiveSmallIntegerField上的范围，相反，它会为这个字段创建一个小整数(在postgres中)，如果指定的数字超出范围，就会得到一个DB错误。|3113900|希望这能有所帮助:)更多关于Validators+in+Django的信息。|offset|length|3113901|PS。我的答案基于django.core.validators中的BaseValidator，但是除了代码之外，一切都是不同的。|3113902|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.djangoproject.com/en/1.7/ref/validators/^0|0|0|0|0|0|0|E|K|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|17|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|18|8|@]|9|@$Q|19|R|1A|1|1B]]|A|$]]|$1|S|3|T|5|6|7|1C|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11]]]]

Here is the best solution if you want some extra flexibility and don't want to change your model field. Just add this custom validator:

<pre><code>#Imports
from django.core.exceptions import ValidationError 

class validate_range_or_null(object):
 compare = lambda self, a, b, c: a &gt; c or a &lt; b
 clean = lambda self, x: x
 message = ('Ensure this value is between %(limit_min)s and %(limit_max)s (it is %(show_value)s).')
 code = 'limit_value'

 def __init__(self, limit_min, limit_max):
 self.limit_min = limit_min
 self.limit_max = limit_max

 def __call__(self, value):
 cleaned = self.clean(value)
 params = {'limit_min': self.limit_min, 'limit_max': self.limit_max, 'show_value': cleaned}
 if value: # make it optional, remove it to make required, or make required on the model
 if self.compare(cleaned, self.limit_min, self.limit_max):
 raise ValidationError(self.message, code=self.code, params=params)
</code></pre>

And it can be used as such:

<pre><code>class YourModel(models.Model):

 ....
 no_dependents = models.PositiveSmallIntegerField("How many dependants?", blank=True, null=True, default=0, validators=[validate_range_or_null(1,100)])
</code></pre>

The two parameters are max and min, and it allows nulls. You can customize the validator if you like by getting rid of the marked if statement or change your field to be blank=False, null=False in the model. That will of course require a migration.

Note: I had to add the validator because Django does not validate the range on PositiveSmallIntegerField, instead it creates a smallint (in postgres) for this field and you get a DB error if the numeric specified is out of range.

Hope this helps :) More on <a href="https://docs.djangoproject.com/en/1.7/ref/validators/" rel="noreferrer">Validators in Django</a>.

PS. I based my answer on BaseValidator in django.core.validators, but everything is different except for the code.

blocks|key|3113904|text|在forms.py中|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3113905|Class+FloatForm(forms.ModelForm):

++++class+Meta:
++++++++model+=+Float
++++++++fields+=+('name','country',+'city',+'point',+'year')

++++def+__init__(self,+*args,+**kwargs):
++++++++super().__init__(*args,+**kwargs)
++++++++self.fields['point']+=+forms.FloatField(max_value=100,+min_value=1)|code-block|syntax|javascript|3113906|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In the forms.py
<pre><code>Class FloatForm(forms.ModelForm):

 class Meta:
 model = Float
 fields = ('name','country', 'city', 'point', 'year')

 def __init__(self, *args, **kwargs):
 super().__init__(*args, **kwargs)
 self.fields['point'] = forms.FloatField(max_value=100, min_value=1)
</code></pre>

Django has various numeric fields available for use in models, e.g. <a href="http://docs.djangoproject.com/en/dev/ref/models/fields/#decimalfield" rel="noreferrer">DecimalField</a> and <a href="http://docs.djangoproject.com/en/dev/ref/models/fields/#positiveintegerfield" rel="noreferrer">PositiveIntegerField</a>. Although the former can be restricted to the number of decimal places stored and the overall number of characters stored, is there any way to restrict it to storing only numbers within a certain range, e.g. 0.0-5.0 ?

Failing that, is there any way to restrict a PositiveIntegerField to only store, for instance, numbers up to 50?

Update: now that Bug 6845 <a href="http://code.djangoproject.com/ticket/6845#comment:71" rel="noreferrer">has been closed</a>, this StackOverflow question may be moot. - sampablokuper

How to limit the maximum value of a numeric field in a Django model?

Django

Django有各种可在模型中使用的数字字段，例如和。虽然前者可以限制为存储的小数位数和存储的总字符数，但有没有办法将其限制为仅存储一定范围内的数字，例如0.0-5.0？如果做不到这一点，有没有办法限制PositiveIntegerField只存储数字，例如，最多存储50个数字？更新:现在错误6845 ，这个StackO...

问如何在Django模型中限制数值字段的最大值？
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