class RuleNode(models.Model):
rule = ...
node = ....
field = ...
class Meta:
unique_together = [[rule, field], [node, field]]{
"non_field_errors": [
"The fields rule, field must make a unique set."
]
}
from django.core.exceptions import NON_FIELD_ERRORS
from django.forms import ModelForm
class ArticleForm(ModelForm):
class Meta:
error_messages = {
NON_FIELD_ERRORS: {
'unique_together': "%(model_name)s's %(field_labels)s are not unique.",
}
}
def unique_error_message(self, model_class, unique_check):
opts = model_class._meta
params = {
'model': self,
'model_class': model_class,
'model_name': capfirst(opts.verbose_name),
'unique_check': unique_check,
}
# A unique field
if len(unique_check) == 1:
field = opts.get_field(unique_check[0])
params['field_label'] = capfirst(field.verbose_name)
return ValidationError(
message=field.error_messages['unique'],
code='unique',
params=params,
)
# unique_together
else:
field_labels = [capfirst(opts.get_field(f).verbose_name) for f in unique_check]
params['field_labels'] = get_text_list(field_labels, _('and'))
return ValidationError(
message=_("%(model_name)s with this %(field_labels)s already exists."),
code='unique_together',
params=params,
)