Commit 267dc4ad authored by Jon Dufresne's avatar Jon Dufresne Committed by Tim Graham
Browse files

Fixed #4136 -- Made ModelForm save empty values for nullable CharFields as NULL. 

Previously, empty values were saved as strings.
parent f2c0eb19

django/db/models/base.py

+5 −3
Original line number Diff line number Diff line
@@ -13,8 +13,8 @@ from django.core.exceptions import ( 
    ObjectDoesNotExist, ValidationError,

)

from django.db import (

    DEFAULT_DB_ALIAS, DJANGO_VERSION_PICKLE_KEY, DatabaseError, connections,

    router, transaction,

    DEFAULT_DB_ALIAS, DJANGO_VERSION_PICKLE_KEY, DatabaseError, connection,

    connections, router, transaction,

)

from django.db.models import signals

from django.db.models.constants import LOOKUP_SEP
@@ -1087,7 +1087,9 @@ class Model(six.with_metaclass(ModelBase)): 
            for field_name in unique_check:

                f = self._meta.get_field(field_name)

                lookup_value = getattr(self, f.attname)

                if lookup_value is None:

                # TODO: Handle multiple backends with different feature flags.

                if (lookup_value is None or

                        (lookup_value == '' and connection.features.interprets_empty_strings_as_nulls)):

                    # no value, skip the lookup

                    continue

                if f.primary_key and not self._state.adding:

django/db/models/fields/__init__.py

+3 −0
Original line number Diff line number Diff line
@@ -1086,6 +1086,9 @@ class CharField(Field): 
        # will be validated twice. This is considered acceptable since we want

        # the value in the form field (to pass into widget for example).

        defaults = {'max_length': self.max_length}

        # TODO: Handle multiple backends with different feature flags.

        if self.null and not connection.features.interprets_empty_strings_as_nulls:

            defaults['empty_value'] = None

        defaults.update(kwargs)

        return super(CharField, self).formfield(**defaults)

django/forms/fields.py

+3 −2
Original line number Diff line number Diff line
@@ -214,10 +214,11 @@ class Field(object): 




class CharField(Field):

    def __init__(self, max_length=None, min_length=None, strip=True, *args, **kwargs):

    def __init__(self, max_length=None, min_length=None, strip=True, empty_value='', *args, **kwargs):

        self.max_length = max_length

        self.min_length = min_length

        self.strip = strip

        self.empty_value = empty_value

        super(CharField, self).__init__(*args, **kwargs)

        if min_length is not None:

            self.validators.append(validators.MinLengthValidator(int(min_length)))
@@ -227,7 +228,7 @@ class CharField(Field): 
    def to_python(self, value):

        "Returns a Unicode object."

        if value in self.empty_values:

            return ''

            return self.empty_value

        value = force_text(value)

        if self.strip:

            value = value.strip()

docs/ref/forms/fields.txt

+7 −1
Original line number Diff line number Diff line
@@ -361,7 +361,7 @@ For each field, we describe the default widget used if you don't specify 
.. class:: CharField(**kwargs)



    * Default widget: :class:`TextInput`

    * Empty value: ``''`` (an empty string)

    * Empty value: Whatever you've given as :attr:`empty_value`.

    * Normalizes to: A Unicode object.

    * Validates ``max_length`` or ``min_length``, if they are provided.

      Otherwise, all inputs are valid.
@@ -380,6 +380,12 @@ For each field, we describe the default widget used if you don't specify 
       If ``True`` (default), the value will be stripped of leading and

       trailing whitespace.



    .. attribute:: empty_value



       .. versionadded:: 1.11



       The value to use to represent "empty". Defaults to an empty string.



``ChoiceField``

---------------

docs/ref/models/fields.txt

+5 −3
Original line number Diff line number Diff line
@@ -43,11 +43,13 @@ If ``True``, Django will store empty values as ``NULL`` in the database. Default 
is ``False``.



Avoid using :attr:`~Field.null` on string-based fields such as

:class:`CharField` and :class:`TextField` because empty string values will

always be stored as empty strings, not as ``NULL``. If a string-based field has

:class:`CharField` and :class:`TextField`. If a string-based field has

``null=True``, that means it has two possible values for "no data": ``NULL``,

and the empty string. In most cases, it's redundant to have two possible values

for "no data;" the Django convention is to use the empty string, not ``NULL``.

for "no data;" the Django convention is to use the empty string, not

``NULL``. One exception is when a :class:`CharField` has both ``unique=True``

and ``blank=True`` set. In this situation, ``null=True`` is required to avoid

unique constraint violations when saving multiple objects with blank values.



For both string-based and non-string-based fields, you will also need to

set ``blank=True`` if you wish to permit empty values in forms, as the