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

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Django has various numeric fields available for use in models, e.g. DecimalField and PositiveIntegerField. 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 has been closed, this StackOverflow question may be moot. – sampablokuper

Best Answer

You can use Django's built-in validators—

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)
        ]
     )

Edit: When working directly with the model, make sure to call the model full_clean method before saving the model in order to trigger the validators. This is not required when using ModelForm since the forms will do that automatically.

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