Commit b58a260c authored by Malcolm Tredinnick's avatar Malcolm Tredinnick
Browse files

Fixed #9431 -- Added extra validation for VARCHAR-based fields on MySQL. 

max_length > 255 and unique=True is not permitted. Based on a patch from
adamnelson.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9650 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent fddc0c58

django/db/backends/mysql/validation.py

+21 −6
Original line number Diff line number Diff line
@@ -2,12 +2,27 @@ from django.db.backends import BaseDatabaseValidation 


class DatabaseValidation(BaseDatabaseValidation):

    def validate_field(self, errors, opts, f):

        "Prior to MySQL 5.0.3, character fields could not exceed 255 characters"

        """

        There are some field length restrictions for MySQL:



        - Prior to version 5.0.3, character fields could not exceed 255

          characters in length.

        - No character (varchar) fields can have a length exceeding 255

          characters if they have a unique index on them.

        """

        from django.db import models

        from django.db import connection

        db_version = connection.get_server_version()

        if db_version < (5, 0, 3) and isinstance(f, (models.CharField, models.CommaSeparatedIntegerField, models.SlugField)) and f.max_length > 255:

            errors.add(opts,

                '"%s": %s cannot have a "max_length" greater than 255 when you are using a version of MySQL prior to 5.0.3 (you are using %s).' % 

                (f.name, f.__class__.__name__, '.'.join([str(n) for n in db_version[:3]])))

        varchar_fields = (models.CharField, models.CommaSeparatedIntegerField,

                models.SlugField)

        if isinstance(f, varchar_fields) and f.max_length > 255:

            if db_version < (5, 0, 3):

                msg = '"%(name)s": %(cls)s cannot have a "max_length" greater than 255 when you are using a version of MySQL prior to 5.0.3 (you are using %(version)s).'

            if f.unique == True:

                msg = '"%(name)s": %(cls)s cannot have a "max_length" greater than 255 when using "unique=True".'

            else:

                msg = None



            if msg:

                errors.add(opts, msg % {'name': f.name, 'cls': f.__class__.__name__, 'version': '.'.join([str(n) for n in db_version[:3]])})

docs/ref/databases.txt

+18 −2
Original line number Diff line number Diff line
@@ -234,8 +234,11 @@ storage engine, you have a couple of options. 


.. _AlterModelOnSyncDB: http://code.djangoproject.com/wiki/AlterModelOnSyncDB



Boolean fields in Django

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

Notes on specific fields

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



Boolean fields

~~~~~~~~~~~~~~



Since MySQL doesn't have a direct ``BOOLEAN`` column type, Django uses a

``TINYINT`` column with values of ``1`` and ``0`` to store values for the
@@ -244,6 +247,19 @@ of that field for more details, but usually this won't be something that will 
matter unless you're printing out the field values and are expecting to see

``True`` and ``False.``.



Character fields

~~~~~~~~~~~~~~~~



Any fields that are stored with ``VARCHAR`` column types have their

``max_length`` restricted to 255 characters if you are using ``unique=True``

for the field. This affects :class:`~django.db.models.CharField`,

:class:`~django.db.models.SlugField` and

:class:`~django.db.models.CommaSeparatedIntegerField`.



Furthermore, if you are using a version of MySQL prior to 5.0.3, all of those

column types have a maximum length restriction of 255 characters, regardless

of whether ``unique=True`` is specified or not.



.. _sqlite-notes:



SQLite notes

docs/ref/models/fields.txt

+13 −4
Original line number Diff line number Diff line
@@ -327,6 +327,13 @@ The admin represents this as an ``<input type="text">`` (a single-line input). 
    The maximum length (in characters) of the field. The max_length is enforced

    at the database level and in Django's validation.



.. note::



    If you are writing an application that must be portable to multiple

    database backends, you should be aware that there are restrictions on

    ``max_length`` for some backends. Refer to the :ref:`database backend

    notes <ref-databases>` for details.



.. admonition:: MySQL users



    If you are using this field with MySQLdb 1.2.2 and the ``utf8_bin``
@@ -341,7 +348,8 @@ The admin represents this as an ``<input type="text">`` (a single-line input). 
.. class:: CommaSeparatedIntegerField(max_length=None, [**options])



A field of integers separated by commas. As in :class:`CharField`, the

:attr:`~CharField.max_length` argument is required.

:attr:`~CharField.max_length` argument is required and the note about database

portability mentioned there should be heeded.



``DateField``

-------------
@@ -654,9 +662,10 @@ Like a :class:`PositiveIntegerField`, but only allows values under a certain 
containing only letters, numbers, underscores or hyphens. They're generally used

in URLs.



Like a CharField, you can specify :attr:`~CharField.max_length`. If

:attr:`~CharField.max_length` is not specified, Django will use a default length

of 50.

Like a CharField, you can specify :attr:`~CharField.max_length` (read the note

about database portability and :attr:`~CharField.max_length` in that section,

too). If :attr:`~CharField.max_length` is not specified, Django will use a

default length of 50.



Implies setting :attr:`Field.db_index` to ``True``.