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Fixed #35671 -- Clarified string-based fields behavior when null=False.

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Clifford Gama 2024-08-14 12:42:33 +02:00 committed by Sarah Boyce
parent 0ebed5fa95
commit ca1318988c
1 changed files with 9 additions and 7 deletions
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docs/ref/models/fields.txt
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@ -43,13 +43,15 @@ If ``True``, Django will store empty values as ``NULL`` in the database. Default
is ``False``. is ``False``.
Avoid using :attr:`~Field.null` on string-based fields such as Avoid using :attr:`~Field.null` on string-based fields such as
:class:`CharField` and :class:`TextField`. If a string-based field has :class:`CharField` and :class:`TextField`. The Django convention is to use an
``null=True``, that means it has two possible values for "no data": ``NULL``, empty string, not ``NULL``, as the "no data" state for string-based fields. If a
and the empty string. In most cases, it's redundant to have two possible values string-based field has ``null=False``, empty strings can still be saved for "no
for "no data;" the Django convention is to use the empty string, not data". If a string-based field has ``null=True``, that means it has two possible
``NULL``. One exception is when a :class:`CharField` has both ``unique=True`` values for "no data": ``NULL``, and the empty string. In most cases, it's
and ``blank=True`` set. In this situation, ``null=True`` is required to avoid redundant to have two possible values for "no data". One exception is when a
unique constraint violations when saving multiple objects with blank values. :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 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 set ``blank=True`` if you wish to permit empty values in forms, as the