Question

我已经在stackoverflow和google上阅读了很多其他帖子，但我找不到解决方案。

当我将模型从CharField更改为ForeignKey时，一切都开始了。我收到的错误是：

Operations to perform:
  Synchronize unmigrated apps: gis, staticfiles, crispy_forms, geoposition, messages
  Apply all migrations: venues, images, amenities, cities_light, registration, auth, admin, sites, sessions, contenttypes, easy_thumbnails, newsletter
Synchronizing apps without migrations:
  Creating tables...
    Running deferred SQL...
  Installing custom SQL...
Running migrations:
  Rendering model states... DONE
  Applying venues.0016_auto_20160514_2141...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.IntegrityError: column "venue_city" contains null values

我的模型如下：

class Venue(models.Model):
    venue_city = models.ForeignKey(City, null=True,)
    venue_country=models.ForeignKey(Country, null=True)

venue_country之前不存在，因此迁移成功。但是venue_city是CharField。

我对迁移文件进行了一些更改，以便它按如下方式执行sql：

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('venues', '0011_venue_map_activation'),
    ]

    migrations.RunSQL(''' ALTER TABLE venues_venue ALTER venue_city TYPE integer USING  venue_city::integer '''),

    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'''),

提前致谢！

更新：我的新迁移文件：

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('cities_light', '0006_compensate_for_0003_bytestring_bug'),
        ('venues', '0024_remove_venue_venue_city'),
    ]

    operations = [
        migrations.AddField(
            model_name='venue',
            name='venue_city',
            field=models.ForeignKey(null=True, to='cities_light.City'),
        ),
    ]

Answer 1

看起来您在创建迁移文件后添加了null=True。因为venue_city不是迁移文件中的可空字段

请按照以下步骤操作。

1) Drop venue_city & venue_country from your local table
3) Delete all the migration files you created for these `CharField to a ForeignKey` change
4) execute `python manage.py makemigrations`
5) execute 'python manage.py migrate'

应该有效

Answer 2

有一个类似的问题我通过删除以前的迁移文件解决了它。没有技术解释

Answer 3

请遵循以下步骤：-

添加 null = True，空白= True 例如：venue_city = models.ForeignKey（City，null = True，空白= True）
删除 venues.0016_auto_20160514_2141 迁移文件
然后运行 python manage.py makemigrations
然后运行 python manage.py migration

无需删除表或从迁移表中删除迁移

Answer 4

我通过将null = True添加到引起问题的（自动生成的）迁移文件和模型中来解决了该问题。然后再次migrate，您失败的迁移现在将成功。在模型中也进行了更改后，makemigration之后将不会检测到任何更改。

Answer 5

我通过以下方法解决了该问题：

首先删除遇到问题的最后一次迁移
然后添加venue_city = models.CharField(blank=True, null=True)
最后使用makemigrations和migrate命令

django.db.utils.IntegrityError：列“venue_city”包含空值

5 个答案: