python编程软件推荐搜易网优化的效果如何
jcLee95的博客：https://blog.csdn.net/qq_28550263
本文地址：https://blog.csdn.net/qq_28550263/article/details/132862795
1. 描述
由于历史的迁移历史的混乱状态导致尝试运行 python manage.py migrate 时，Django 试图创建数据库表时发生了问题。错误信息中提到了缺少 django_content_type 表，这是Django用于跟踪模型的ContentType的表。
错误大致信息如下：
Operations to perform:Apply all migrations: admin, auth, contenttypes, sessions, users
Running migrations:No migrations to apply.
Traceback (most recent call last):File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 89, in _executereturn self.cursor.execute(sql, params)^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\backends\sqlite3\base.py", line 357, in executereturn Database.Cursor.execute(self, query, params)^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sqlite3.OperationalError: no such table: django_content_typeThe above exception was the direct cause of the following exception:Traceback (most recent call last):File "D:\desktop\jcmusic\manage.py", line 22, in <module>main()File "D:\desktop\jcmusic\manage.py", line 18, in mainexecute_from_command_line(sys.argv)File "C:\Python311\Lib\site-packages\django\core\management\__init__.py", line 446, in execute_from_command_lineutility.execute()File "C:\Python311\Lib\site-packages\django\core\management\__init__.py", line 440, in executeself.fetch_command(subcommand).run_from_argv(self.argv)File "C:\Python311\Lib\site-packages\django\core\management\base.py", line 402, in run_from_argvself.execute(*args, **cmd_options)File "C:\Python311\Lib\site-packages\django\core\management\base.py", line 448, in executeoutput = self.handle(*args, **options)^^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\core\management\base.py", line 96, in wrappedres = handle_func(*args, **kwargs)^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\core\management\commands\migrate.py", line 376, in handleemit_post_migrate_signal(File "C:\Python311\Lib\site-packages\django\core\management\sql.py", line 52, in emit_post_migrate_signalmodels.signals.post_migrate.send(File "C:\Python311\Lib\site-packages\django\dispatch\dispatcher.py", line 176, in sendreturn [^File "C:\Python311\Lib\site-packages\django\dispatch\dispatcher.py", line 177, in <listcomp>(receiver, receiver(signal=self, sender=sender, **named))^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\contrib\auth\management\__init__.py", line 51, in create_permissionscreate_contenttypes(File "C:\Python311\Lib\site-packages\django\contrib\contenttypes\management\__init__.py", line 127, in create_contenttypescontent_types, app_models = get_contenttypes_and_models(^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\contrib\contenttypes\management\__init__.py", line 98, in get_contenttypes_and_modelscontent_types = {^File "C:\Python311\Lib\site-packages\django\db\models\query.py", line 394, in __iter__self._fetch_all()File "C:\Python311\Lib\site-packages\django\db\models\query.py", line 1867, in _fetch_allself._result_cache = list(self._iterable_class(self))^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\models\query.py", line 87, in __iter__results = compiler.execute_sql(^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\models\sql\compiler.py", line 1398, in execute_sqlcursor.execute(sql, params)File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 102, in executereturn super().execute(sql, params)^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 67, in executereturn self._execute_with_wrappers(^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 80, in _execute_with_wrappersreturn executor(sql, params, many, context)^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 84, in _executewith self.db.wrap_database_errors:File "C:\Python311\Lib\site-packages\django\db\utils.py", line 91, in __exit__raise dj_exc_value.with_traceback(traceback) from exc_valueFile "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 89, in _executereturn self.cursor.execute(sql, params)^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^File "C:\Python311\Lib\site-packages\django\db\backends\sqlite3\base.py", line 357, in executereturn Database.Cursor.execute(self, query, params)^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
django.db.utils.OperationalError: no such table: django_content_type
我决定使用 Django Shell 清空数据库表。记录一下过程。
2. 步骤
备份重要数据
清理前，确保你使用各种手段备份过了所有重要数据，然后才清空数据库中的所有表。
进入 Django Shell
python manage.py shell
输入脚本
拷贝以下写好的删表脚本到交互式Shell中，键入回车开始执行。
from django.db import connection
cursor = connection.cursor()
cursor.execute("SELECT name FROM sqlite_master WHERE type='table';")
tables = cursor.fetchall()
for table in tables:cursor.execute(f"DELETE FROM {table[0]};")
然后输入exit函数退出该Django Shell环境。
exit()
可以了，现在可以重新创建迁移和数据库表了：
python manage.py makemigrations
python manage.py migrate