id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35671	Clarify behavior for Field.null=False on string-based fields	Clifford Gama	Clifford Gama	"My concern is with the usage of `Field.null=False`, which differs from its expected practical application, rather than just its technical function.

When `Field.null=False` and `Field.default` is not set for string-based fields—such as `CharField`, `TextField`, and `SlugField`—`Field.null` does not raise the expected `IntegrityError: NOT NULL constraint failed` when a value is not provided for the field.

Django saves empty strings for these fields, and since the database does not (always?) interpret an empty string as NULL, they are accepted without raising the `IntegrityError`. This behavior is not clearly documented and is inconsistent with the typical usage of `Field.null` as a NOT NULL constraint.

The [documentation](https://docs.djangoproject.com/en/5.1/ref/models/fields/#django.db.models.Field.null) on `Field.null` specifies:

> Avoid using null on string-based fields such as CharField and 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.

What is not specified here or in the documentation for `Field.default` is that Django effectively sets the empty string as the default for these string-based fields when none is provided. If you wish to truly disallow empty values for those fields, you need to set `Field.default=None` and `null=False`.

Since Django relies on the database to raise `IntegrityError`s when a required field is not provided, it is inconsistent that Django does not treat the empty string as “no data” (i.e., NULL) in this context or that they use the empty string as “no data” when the database will interpret it as actual data.

The issue is particularly evident when a model instance is created using the model Manager's `create()` and `get_or_create()` methods or by direct instantiation.
"	Cleanup/optimization	closed	Database layer (models, ORM)	5.1	Normal	fixed	Field.null; IntegrityError; NotNullConstraint; Field.default	Clifford Gama	Ready for checkin	1	0	0	0	0	0