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| -rw-r--r-- | docs/topics/forms/modelforms.txt | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/docs/topics/forms/modelforms.txt b/docs/topics/forms/modelforms.txt index 07c7b02c19..07a2819fa3 100644 --- a/docs/topics/forms/modelforms.txt +++ b/docs/topics/forms/modelforms.txt @@ -331,13 +331,17 @@ Since the Author model has only 3 fields, 'name', 'title', and .. note:: If you specify ``fields`` or ``exclude`` when creating a form with - ``ModelForm``, then the fields that are not in the resulting form will not - be set by the form's ``save()`` method. Django will prevent any attempt to - save an incomplete model, so if the model does not allow the missing fields - to be empty, and does not provide a default value for the missing fields, - any attempt to ``save()`` a ``ModelForm`` with missing fields will fail. - To avoid this failure, you must instantiate your model with initial values - for the missing, but required fields:: + ``ModelForm``, then the fields that are not in the resulting form + will not be set by the form's ``save()`` method. Also, if you + manually add the excluded fields back to the form, they will not + be initialized from the model instance. + + Django will prevent any attempt to save an incomplete model, so if + the model does not allow the missing fields to be empty, and does + not provide a default value for the missing fields, any attempt to + ``save()`` a ``ModelForm`` with missing fields will fail. To + avoid this failure, you must instantiate your model with initial + values for the missing, but required fields:: author = Author(title='Mr') form = PartialAuthorForm(request.POST, instance=author) @@ -632,6 +636,12 @@ database. If a given instance's data didn't change in the bound data, the instance won't be saved to the database and won't be included in the return value (``instances``, in the above example). +When fields are missing from the form (for example because they have +been excluded), these fields will not be set by the ``save()`` +method. You can find more information about this restriction, which +also holds for regular ``ModelForms``, in `Using a subset of fields on +the form`_. + Pass ``commit=False`` to return the unsaved model instances:: # don't save to the database |