models 中 设置 Meta unique_together(models.py):
class Item(models.Model):
text = models.TextField(default='')
list = models.ForeignKey(List, default=None)
class Meta:
ordering = ('id',)
unique_together = ('list', 'text')
def __str__(self):
return self.text
django.db.utils.IntegrityError: UNIQUE constraint failed: lists_item.list_id,
lists_item.text
ModelForm 中设置 instance（forms.py）
class ItemForm(forms.models.ModelForm):
class Meta:
model = Item
fields = ('text',)
widgets = {
'text': forms.fields.TextInput(attrs={
'placeholder': 'Enter a to-do item',
'class': 'form-control input-lg',
}),
}
error_messages = {
'text': {'required': EMPTY_ITEM_ERROR}
}
def save(self, for_list):
self.instance.list = for_list
return super().save()
class ExistingListItemForm(ItemForm):
def __init__(self, for_list, *args, **kwargs):
super().__init__(*args, **kwargs)
self.instance.list = for_list
def validate_unique(self):
try:
self.instance.validate_unique()
except ValidationError as e:
e.error_dict = {'text': [DUPLICATE_ITEM_ERROR]}
self._update_errors(e)
def save(self):
return forms.models.ModelForm.save(self)
这样就可以在表单提交后检查是否有不唯一的字段了。
