问题
I'm working on a django project and have had some migration troubles in my (test)prod setting and as a consequence have I dumped all relevant data and I am now in the process of setting up the database from scratch.
Here is what happens:
- I remove all (potentially) faulty migrations from the app
- I run makemigrations
- I run migrate
- I am presented with the following error:
Error:
C:\Users\Sverker\Dropbox\Picrates>python manage.py makemigrations db_trans
C:\Users\Sverker\Dropbox\Picrates\picrates_project
Migrations for 'db_trans':
0001_initial.py:
- Create model Language
- Create model Markup
- Create model String
- Create model TransMarkup
- Create model TransString
- Add field trans_string to string
- Alter unique_together for string (1 constraint(s))
- Add field trans_markup to markup
- Alter unique_together for markup (1 constraint(s))
C:\Users\Sverker\Dropbox\Picrates>python manage.py migrate
C:\Users\Sverker\Dropbox\Picrates\picrates_project
Operations to perform:
Synchronize unmigrated apps: allauth, linkedin_oauth2, crispy_forms
Apply all migrations: account, sessions, admin, db_trans, sites, auth, contenttypes, parties, ped, socialaccount
Synchronizing apps without migrations:
Creating tables...
Installing custom SQL...
Installing indexes...
Running migrations:
Applying db_trans.0001_initial...Traceback (most recent call last):
File "manage.py", line 15, in <module>
execute_from_command_line(sys.argv)
File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 385, in execute_from_command_line
utility.execute()
File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Python27\lib\site-packages\django\core\management\base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "C:\Python27\lib\site-packages\django\core\management\base.py", line 338, in execute
output = self.handle(*args, **options)
File "C:\Python27\lib\site-packages\django\core\management\commands\migrate.py", line 161, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 68, in migrate
self.apply_migration(migration, fake=fake)
File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 102, in apply_migration
migration.apply(project_state, schema_editor)
File "C:\Python27\lib\site-packages\django\db\migrations\migration.py", line 108, in apply
operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
File "C:\Python27\lib\site-packages\django\db\migrations\operations\models.py", line 36, in database_forwards
schema_editor.create_model(model)
File "C:\Python27\lib\site-packages\django\db\backends\schema.py", line 213, in create_model
definition, extra_params = self.column_sql(model, field)
File "C:\Python27\lib\site-packages\django\db\backends\schema.py", line 125, in column_sql
default_value = self.effective_default(field)
File "C:\Python27\lib\site-packages\django\db\backends\schema.py", line 175, in effective_default
default = field.get_default()
File "C:\Python27\lib\site-packages\django\db\models\fields\__init__.py", line 719, in get_default
return self.default()
File "C:\Users\Sverker\Dropbox\Picrates\db_trans\models.py", line 9, in get_default_priority
max = Language.objects.all().aggregate(models.Max("fallback_priority"))["fallback_priority__max"]
File "C:\Python27\lib\site-packages\django\db\models\query.py", line 325, in aggregate
return query.get_aggregation(using=self.db, force_subq=force_subq)
File "C:\Python27\lib\site-packages\django\db\models\sql\query.py", line 402, in get_aggregation
result = query.get_compiler(using).execute_sql(SINGLE)
File "C:\Python27\lib\site-packages\django\db\models\sql\compiler.py", line 786, in execute_sql
cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\sqlite3\base.py", line 485, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: db_trans_language
Here is the created migration:
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models, migrations
import markupfield.fields
import db_trans.models
class Migration(migrations.Migration):
dependencies = [
]
operations = [
migrations.CreateModel(
name='Language',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('code', models.CharField(max_length=3)),
('language', models.CharField(max_length=50)),
('is_public', models.BooleanField(default=False)),
('fallback_priority', models.PositiveIntegerField(default=db_trans.models.get_default_priority, help_text=b'Lowest value will be first fallback language.', unique=True)),
],
options={
},
bases=(models.Model,),
),
migrations.CreateModel(
name='Markup',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('markup', markupfield.fields.MarkupField()),
('markup_markup_type', models.CharField(default=b'markdown', max_length=30, editable=False, choices=[(b'', b'--'), (b'html', b'html'), (b'plain', b'plain'), (b'markdown', b'markdown')])),
('_markup_rendered', models.TextField(editable=False)),
('language', models.ForeignKey(to='db_trans.Language')),
],
options={
},
bases=(models.Model,),
),
migrations.CreateModel(
name='String',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('string', models.CharField(max_length=256)),
('language', models.ForeignKey(to='db_trans.Language')),
],
options={
},
bases=(models.Model,),
),
migrations.CreateModel(
name='TransMarkup',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('key', models.CharField(unique=True, max_length=50, db_index=True)),
('verbose_name', models.CharField(max_length=200, null=True, blank=True)),
],
options={
'verbose_name': 'Translated Markup',
},
bases=(models.Model,),
),
migrations.CreateModel(
name='TransString',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('key', models.CharField(unique=True, max_length=50, db_index=True)),
('verbose_name', models.CharField(max_length=200, null=True, blank=True)),
],
options={
'verbose_name': 'Translated String',
},
bases=(models.Model,),
),
migrations.AddField(
model_name='string',
name='trans_string',
field=models.ForeignKey(related_name='strings', to='db_trans.TransString'),
preserve_default=True,
),
migrations.AlterUniqueTogether(
name='string',
unique_together=set([('trans_string', 'language')]),
),
migrations.AddField(
model_name='markup',
name='trans_markup',
field=models.ForeignKey(related_name='markups', to='db_trans.TransMarkup'),
preserve_default=True,
),
migrations.AlterUniqueTogether(
name='markup',
unique_together=set([('trans_markup', 'language')]),
),
]
models.py:
from django.db import models
from django.template.loader import render_to_string
from django.utils.translation import get_language
from markupfield.fields import MarkupField
def get_default_priority():
max = Language.objects.all().aggregate(models.Max("fallback_priority"))["fallback_priority__max"]
if max:
return max + 10
return 50
class Language(models.Model):
code = models.CharField(
max_length=3,
null=False,
blank=False,
)
language = models.CharField(
max_length=50,
)
is_public = models.BooleanField(
default=False,
)
fallback_priority = models.PositiveIntegerField(
null=False,
unique=True,
default=get_default_priority,
help_text="Lowest value will be first fallback language."
)
def __unicode__(self):
unicode = self.code
if self.language:
unicode += u" - " + self.language
return unicode
class TransPhrase(models.Model):
key = models.CharField(
max_length=50,
unique=True,
null=False,
blank=False,
db_index=True,
)
verbose_name = models.CharField(
max_length=200,
null=True,
blank=True,
)
@classmethod
def get_translation(cls, key, description=None):
trans_phrase, created = cls.objects.get_or_create(key=key)
if not description:
trans_phrase.verbose_name = description
trans_phrase.save()
return trans_phrase
def render(self, wrap, csrf_token):
raise NotImplementedError
class Meta:
abstract = True
class TransMarkup(TransPhrase):
def get_trans(self, language_code, use_fallback=True):
try:
return self.markups.get(language__code=language_code)
except Markup.DoesNotExist:
if use_fallback:
fallback_markups = self.markups.all().order_by("language__fallback_priority")
if fallback_markups:
return fallback_markups[0]
language = Language.objects.get(code=language_code)
return Markup(trans_markup=self, language=language)
def __unicode__(self):
return u"[" + self.key + u"]"
def render(self, wrap, csrf_token):
from db_trans.forms import SetTransMarkupForm
markup = self.get_trans(get_language(), use_fallback=(not wrap))
if wrap:
context = {
"csrf_token": csrf_token,
"form": SetTransMarkupForm(instance=markup),
"trans_markup": markup
}
return render_to_string("db_trans/set_markup.html", context)
else:
return markup
class Meta:
verbose_name = "Translated Markup"
class Markup(models.Model):
markup = MarkupField(
markup_type="markdown"
)
trans_markup = models.ForeignKey(
TransMarkup,
null=False,
related_name="markups",
)
language = models.ForeignKey(
Language,
null=False,
)
def __unicode__(self):
if self.markup.rendered:
return self.markup.rendered
return u"[" + self.trans_markup.key + u"]"
class Meta:
unique_together = ("trans_markup", "language")
class TransString(TransPhrase):
def get_trans(self, language_code, use_fallback=True):
try:
return self.strings.get(language__code=language_code)
except String.DoesNotExist:
if use_fallback:
fallback_strings = self.strings.all().order_by("language__fallback_priority")
if fallback_strings:
return fallback_strings[0]
language = Language.objects.get(code=language_code)
return String(trans_string=self, language=language)
def render(self, wrap, csrf_token):
from db_trans.forms import SetTransStringForm
string = self.get_trans(get_language(), use_fallback=(not wrap))
if wrap:
context = {
"csrf_token": csrf_token,
"form": SetTransStringForm(instance=string),
"trans_string": string
}
return render_to_string("db_trans/set_string.html", context)
else:
return string
class Meta:
verbose_name = "Translated String"
class String(models.Model):
string = models.CharField(
max_length=256
)
trans_string = models.ForeignKey(
TransString,
null=False,
related_name="strings"
)
language = models.ForeignKey(
Language,
null=False,
)
def __unicode__(self):
if self.string:
return self.string
return u"[" + self.trans_string.key + u"]"
class Meta:
unique_together = ("trans_string", "language")
Help would be greatly appreciated!
回答1:
I know this is an old question, but I recently had a similar error. The offensive line is probably:
File "C:\Users\Sverker\Dropbox\Picrates\db_trans\models.py", line 9, in get_default_priority
max = Language.objects.all().aggregate(models.Max("fallback_priority"))["fallback_priority__max"]
So here, you are querying the database with Language.objects.all(). This line gets executed before the migrations are actually run, while there's still inconsistency between models.py and the database itself.
Try commenting out that line (and other references to max), and then re-run the migrations. That's what worked for me.
来源：https://stackoverflow.com/questions/29963186/django-1-7-migrations-django-db-utils-operationalerror-no-such-table-db-trans