Question

Having trouble with the db.alter command when changing a date field from null=True and blank=True to required by removing these two values.

When the below line is commented out, the migration runs without a problem.

    db.alter_column('milestones_milestone', 'date', self.gf('django.db.models.fields.DateField')(default='2011-01-01'))

This should change the column description from:

'milestones.milestone': {
  'date': ('django.db.models.fields.DateField', [], {'null': 'True', 'blank': 'True'}),
},

to

'milestones.milestone': {
  'date': ('django.db.models.fields.DateField', [], {default:'2011-01-01'}),
},

When the above line is left in the migration, the error I get:

 - Migrating forwards to 0002_auto__add_field_milestone_type__chg_field_milestone_date__add_field_mi.
 > milestones:0002_auto__add_field_milestone_type__chg_field_milestone_date__add_field_mi
 ! Error found during real run of migration! Aborting.

 ! Since you have a database that does not support running
 ! schema-altering statements in transactions, we have had
 ! to leave it in an interim state between migrations.

! You *might* be able to recover with:   = ALTER TABLE `milestones_milestone` DROP COLUMN `type` CASCADE; []
   = ALTER TABLE `milestones_milestonetemplate` DROP COLUMN `type` CASCADE; []

 ! The South developers regret this has happened, and would
 ! like to gently persuade you to consider a slightly
 ! easier-to-deal-with DBMS.
 ! NOTE: The error which caused the migration to fail is further up.
Traceback (most recent call last):
  File "manage.py", line 11, in <module>
    execute_manager(global_settings)
  File "C:\Python26\lib\site-packages\django\core\management\__init__.py", line 438, in execute_manager
    utility.execute()
  File "C:\Python26\lib\site-packages\django\core\management\__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Python26\lib\site-packages\django\core\management\base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "C:\Python26\lib\site-packages\django\core\management\base.py", line 218, in execute
    output = self.handle(*args, **options)
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\management\commands\migrate.py", line 109, in ha
ndle
    ignore_ghosts = ignore_ghosts,
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\migration\__init__.py", line 202, in migrate_app

    success = migrator.migrate_many(target, workplan, database)
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\migration\migrators.py", line 292, in migrate_ma
ny
    result = self.migrate(migration, database)
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\migration\migrators.py", line 125, in migrate
    result = self.run(migration)
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\migration\migrators.py", line 99, in run
    return self.run_migration(migration)
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\migration\migrators.py", line 81, in run_migrati
on
    migration_function()
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\migration\migrators.py", line 57, in <lambda>
    return (lambda: direction(orm))
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\milestones\migrations\0002_auto__add_field_milestone_type_
_chg_field_milestone_date__add_field_mi.py", line 15, in forwards
    db.alter_column('milestones_milestone', 'date', self.gf('django.db.models.fields.DateField')(default='2011-01-01'))
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\db\generic.py", line 373, in alter_column
    self.execute("ALTER TABLE %s %s;" % (self.quote_name(table_name), sql), values)
  File "C:\SQE_Dashboard\SQE Dashboard-mimercha\SQE Dashboard\dashboard\lib\south\db\generic.py", line 137, in execute
    cursor.execute(sql, params)
  File "C:\Python26\lib\site-packages\django\db\backends\util.py", line 15, in execute
    return self.cursor.execute(sql, params)
  File "C:\Python26\lib\site-packages\django\db\backends\mysql\base.py", line 86, in execute
    return self.cursor.execute(query, args)
  File "C:\Python26\lib\site-packages\MySQLdb\cursors.py", line 173, in execute
    self.errorhandler(self, exc, value)
  File "C:\Python26\lib\site-packages\MySQLdb\connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
django.db.utils.DatabaseError: (1265, "Data truncated for column 'date' at row 512")

I’m using:

South 0.71 Note: I tried upgrading to 0.73 and found 0.73 gave me the same error and broke my scripts when loading older fixtures.

Django 1.2.1

python library: MySQLDdb DB API v2.0 compatible, revision 603

mysql Ver 14.14 Distrib 5.1.51, for Win32 (ia32)

InnoDB Storage Engine

Answer 1

I just ran into the same error. In my case I had accidentally set the column’s default value to datetime.now which caused data truncation.

I’d recommend that you remove the default value from your model, set auto_now_add=True and regenerate the migration file.