Question

我理解这个问题有多少问题，但没有一个解决方案有帮助。我遇到了以下问题：我删除了我的模型并删除了admin.py中的导入。然后我想用makemigrations更新django数据库，这表明它删除了模型员工，但是在使用migrate命令后，我看到了一个错误，表明该关系不存在。我也把它从我使用的postgres数据库中删除了。这里奇怪的是迁移一直在寻找不存在的模型。即使我创建另一个makemigrations检测到它，然后migrate说relation project_employee.. 试过syncdb --all没有成功。这是migrate

的输出

Apply all migrations: sessions, project, admin, auth, contenttypes
Running migrations:
Applying project.0003_auto_20160318_1215...Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
psycopg2.ProgrammingError: relation "project_employee" does not exist


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 "/usr/lib/python3/dist-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
utility.execute()
File "/usr/lib/python3/dist-packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/lib/python3/dist-packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/lib/python3/dist-packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File "/usr/lib/python3/dist-packages/django/core/management/commands/migrate.py", line 161, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/usr/lib/python3/dist-packages/django/db/migrations/executor.py", line 68, in migrate
self.apply_migration(migration, fake=fake)
File "/usr/lib/python3/dist-packages/django/db/migrations/executor.py", line 102, in apply_migration
migration.apply(project_state, schema_editor)
File "/usr/lib/python3/dist-packages/django/db/migrations/migration.py", line 108, in apply
operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
 File "/usr/lib/python3/dist-packages/django/db/migrations/operations/fields.py", line 84, in database_forwards
schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0])
 File "/usr/lib/python3/dist-packages/django/db/backends/schema.py", line 431, in remove_field
self.execute(sql)
 File "/usr/lib/python3/dist-packages/django/db/backends/schema.py", line 111, in execute
cursor.execute(sql, params)
 File "/usr/lib/python3/dist-packages/django/db/backends/utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
 File "/usr/lib/python3/dist-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
 File "/usr/lib/python3/dist-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
 File "/usr/lib/python3/dist-packages/django/utils/six.py", line 658, in reraise
raise value.with_traceback(tb)
 File "/usr/lib/python3/dist-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
 django.db.utils.ProgrammingError: relation "project_employee" does not exist

`

谢谢

Answer 1

我可以通过以下步骤解决此问题

当我运行此命令时

python manage.py migrate app_name zero

它在抱怨缺少某些表。所以我创建了一个带有虚拟列的虚拟表。
我再次运行了命令

python manage.py migrate app_name zero
我已为该应用应用了迁移

python manage.py migrate app_name

Answer 2

最终帮助从项目文件夹中删除整个迁移文件夹。看到一些南方的回应，但没有尝试过。

Answer 3

AFAIK，您不应在迁移之前直接从数据库中删除表。如果您更改了模型，那么manage.py migrate将会执行此操作。

django无法检测到DB的直接变化;只知道模型脚本的变化。因此，如果删除表，则django不会检测到更改，因此django会一直查找已删除的表并给出错误。

有时候迁移无缘无故。在这种情况下，我会做以下事情：

撤消models.py
执行django迁移（manage.py makemigrations appname比manage.py makemigrations更好）
如果迁移有效，则再次更改models.py
再次进行django迁移

这有时会奏效。

Answer 4

使用以下代码在数据库中删除表

python manage.py migrate app_name zero

然后再次迁移

python manage.py migrate app_name

原因是已经存在一个表，并且当您执行“初始迁移”时，Django将看到已经应用了初始迁移，因为该表已经存在于旧模式中，因此不采用新模式具有不同架构的表格。

Answer 5

我需要做的就是创建一个具有相同名称和一个虚拟列的表。然后当我迁移时，django为我重新制作了所有列。

Answer 6

最后这对我有用：

import argparse
import shlex

parser = argparse.ArgumentParser(prog="whatever", description='test argp')
parser.add_argument("--test", help="Test")    

cmd = '--test something'
cmdline = shlex.split(cmd)
         
pargs =  parser.parse_args(cmdline)

Django + posgtres关系不存在错误

6 个答案: