diff options
Diffstat (limited to 'docs/ref')
| -rw-r--r-- | docs/ref/models/instances.txt | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/docs/ref/models/instances.txt b/docs/ref/models/instances.txt index e444067820..60072fdecc 100644 --- a/docs/ref/models/instances.txt +++ b/docs/ref/models/instances.txt @@ -152,9 +152,10 @@ access to more than a single field:: Note, however, that like :meth:`Model.full_clean()`, a model's ``clean()`` method is not invoked when you call your model's :meth:`~Model.save()` method. -Any :exc:`~django.core.exceptions.ValidationError` exceptions raised by -``Model.clean()`` will be stored in a special key error dictionary key, -:data:`~django.core.exceptions.NON_FIELD_ERRORS`, that is used for errors +In the above example, the :exc:`~django.core.exceptions.ValidationError` +exception raised by ``Model.clean()`` was instantiated with a string, so it +will be stored in a special error dictionary key, +:data:`~django.core.exceptions.NON_FIELD_ERRORS`. This key is used for errors that are tied to the entire model instead of to a specific field:: from django.core.exceptions import ValidationError, NON_FIELD_ERRORS @@ -163,6 +164,19 @@ that are tied to the entire model instead of to a specific field:: except ValidationError as e: non_field_errors = e.message_dict[NON_FIELD_ERRORS] +To assign exceptions to a specific field, instantiate the +:exc:`~django.core.exceptions.ValidationError` with a dictionary, where the +keys are the field names. We could update the previous example to assign the +error to the ``pub_date`` field:: + + class Article(models.Model): + ... + def clean(self): + # Don't allow draft entries to have a pub_date. + if self.status == 'draft' and self.pub_date is not None: + raise ValidationError({'pub_date': 'Draft entries may not have a publication date.'}) + ... + Finally, ``full_clean()`` will check any unique constraints on your model. .. method:: Model.validate_unique(exclude=None) |