简记使用 Django Shell 清空所有数据库表
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 _execute return self.cursor.execute(sql, params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\db\backends\sqlite3\base.py", line 357, in execute return Database.Cursor.execute(self, query, params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ sqlite3.OperationalError: no such table: django_content_type The 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 main execute_from_command_line(sys.argv) File "C:\Python311\Lib\site-packages\django\core\management\__init__.py", line 446, in execute_from_command_line utility.execute() File "C:\Python311\Lib\site-packages\django\core\management\__init__.py", line 440, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "C:\Python311\Lib\site-packages\django\core\management\base.py", line 402, in run_from_argv self.execute(*args, **cmd_options) File "C:\Python311\Lib\site-packages\django\core\management\base.py", line 448, in execute output = self.handle(*args, **options) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\core\management\base.py", line 96, in wrapped res = handle_func(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\core\management\commands\migrate.py", line 376, in handle emit_post_migrate_signal( File "C:\Python311\Lib\site-packages\django\core\management\sql.py", line 52, in emit_post_migrate_signal models.signals.post_migrate.send( File "C:\Python311\Lib\site-packages\django\dispatch\dispatcher.py", line 176, in send return [ ^ 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_permissions create_contenttypes( File "C:\Python311\Lib\site-packages\django\contrib\contenttypes\management\__init__.py", line 127, in create_contenttypes content_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_models content_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_all self._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_sql cursor.execute(sql, params) File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 102, in execute return super().execute(sql, params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 67, in execute return self._execute_with_wrappers( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 80, in _execute_with_wrappers return executor(sql, params, many, context) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 84, in _execute with 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_value File "C:\Python311\Lib\site-packages\django\db\backends\utils.py", line 89, in _execute return self.cursor.execute(sql, params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Python311\Lib\site-packages\django\db\backends\sqlite3\base.py", line 357, in execute return 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
