我的目标是使用Django-Cities-Light并将我的模型与foreignkey链接到来自django-cities-light的城市和乡村模型。
当我运行python3 manage.py migrate时，我收到以下错误：
#flights tr:hover i.fa当我运行python3 manage.py sqlmigrate场所0012时，我得到以下追溯：
Operations to perform:
Synchronize unmigrated apps: gis, crispy_forms, geoposition, messages, staticfiles
Apply all migrations: amenities, sites, images, venues, sessions, contenttypes, admin, auth, newsletter, registration, easy_thumbnails, cities_light
Synchronizing apps without migrations:
Creating tables...
Running deferred SQL...
Installing custom SQL...
Running migrations:
Rendering model states... DONE
Applying venues.0012_auto_20160514_2024...Traceback (most recent call last):
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
psycopg2.ProgrammingError: column "venue_city_id" cannot be cast automatically to type integer
HINT: Specify a USING expression to perform the conversion.
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
utility.execute()
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/__init__.py", line 346, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/base.py", line 394, in run_from_argv
self.execute(*args, **cmd_options)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/base.py", line 445, in execute
output = self.handle(*args, **options)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/commands/migrate.py", line 222, in handle
executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/executor.py", line 110, in migrate
self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/executor.py", line 148, in apply_migration
state = migration.apply(state, schema_editor)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/migration.py", line 115, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/operations/fields.py", line 201, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/base/schema.py", line 484, in alter_field
old_db_params, new_db_params, strict)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/base/schema.py", line 636, in _alter_field
params,
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/base/schema.py", line 111, in execute
cursor.execute(sql, params)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/utils.py", line 79, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/utils.py", line 98, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: column "venue_city_id" cannot be cast automatically to type integer
HINT: Specify a USING expression to perform the conversion.
这是0012迁移文件：
Traceback (most recent call last):
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/apps/registry.py", line 148, in get_app_config
return self.app_configs[app_label]
KeyError: 'cities_light'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/state.py", line 238, in __init__
model = self.get_model(lookup_model[0], lookup_model[1])
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/apps/registry.py", line 202, in get_model
return self.get_app_config(app_label).get_model(model_name.lower())
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/apps/registry.py", line 150, in get_app_config
raise LookupError("No installed app with label '%s'." % app_label)
LookupError: No installed app with label 'cities_light'.
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
utility.execute()
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/__init__.py", line 346, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/base.py", line 394, in run_from_argv
self.execute(*args, **cmd_options)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/commands/sqlmigrate.py", line 31, in execute
return super(Command, self).execute(*args, **options)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/base.py", line 445, in execute
output = self.handle(*args, **options)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/core/management/commands/sqlmigrate.py", line 57, in handle
sql_statements = executor.collect_sql(plan)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/executor.py", line 127, in collect_sql
state = migration.apply(state, schema_editor, collect_sql=True)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/migration.py", line 115, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/operations/fields.py", line 186, in database_forwards
to_model = to_state.apps.get_model(app_label, self.model_name)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/utils/functional.py", line 59, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/state.py", line 166, in apps
return StateApps(self.real_apps, self.models)
File "/Users/iam-tony/.envs/venuepark/lib/python3.4/site-packages/django/db/migrations/state.py", line 248, in __init__
raise ValueError(msg.format(field=operations[0][1], model=lookup_model))
ValueError: Lookup failed for model referenced by field venues.Venue.venue_city: cities_light.City
我的模型如下：
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations, models
class Migration(migrations.Migration):
dependencies = [
('venues', '0011_venue_map_activation'),
]
operations = [
migrations.AlterField(
model_name='venue',
name='venue_city',
field=models.ForeignKey(to='cities_light.City', blank=True),
),
]
我的设置如下：
class Venue(models.Model):
venue_owner = models.ForeignKey(User, null=True)
venue_name = models.CharField(max_length=100)
venue_address = models.CharField(max_length=250)
venue_city = models.CharField(max_length=250)
venue_zipcode = models.CharField(max_length=20, blank=True)
venue_seated_capacity = models.PositiveIntegerField()
venue_standing_capacity = models.PositiveIntegerField()
venue_type = models.CharField(max_length=20, choices=VENUE_TYPES)
venue_sqf = models.PositiveIntegerField(default=0)
venue_description = models.TextField(blank=False, null=True)
featurete = models.PositiveIntegerField(default=0)
carousel = models.PositiveIntegerField(default=0)
gallery = models.PositiveIntegerField(default=0)
#map_activation is for activating the map for the venue
map_activation = models.BooleanField(default=False)
position = GeopositionField(blank=True)
这导致错误。将场地_city从charfield改为foreignkey。我尝试更换模型但我仍然遇到同样的错误。
如何修复此错误并创建与Django-cities-models的连接？
答案 0 :(得分：2)
假设您的venue_city列目前包含与城市模型中的主键对应的整数值。您仍然可以通过编辑0012_auto_20160514_2024迁移文件来执行迁移。先做
./manage.py sqlmigrate venues 0012
密切关注与venue_city列对应的生成的SQl位。现在，您需要编辑迁移文件，并使用migrations.RunSQL替换默认生成的迁移。进入它的查询本质上是您使用sqlmigration找到的查询。只需将USING venue_city::integer添加到最后。
更新：根据您更新的答案，您将替换此部分
migrations.AlterField(
model_name='venue',
name='venue_city',
field=models.ForeignKey(to='cities_light.City', blank=True),
),
使用自定义SQL修改列。
更新2 ：由于您无法运行sqlmigrate，我将尝试向您展示SQL应该是什么。
migrations.RunSQL(''' ALTER TABLE venues_venue ALTER venue_city TYPE integer USING venue_city::integer '''),
migrations.RunSQL(''' ALTER TABLE venues_venue ALTER venue_city DROP NOT NULL '''),
migrations.RunSQL(''' ALTER TABLE venues_venue ALTER venue_city RENAME COLUMN venue_city TO venue_city_id '''),
migrations.RunSQL(''' ALTER TABLE venues_venue ADD CONSTRAINT venues_venus_somefk FOREIGN KEY (venue_city_id) REFERENCES cities_light (id) DEFERRABLE INITIALLY DEFERRED'''),
完整查询基本上就是sqlmigrate所显示的内容。