如何解决Django中的错误模特儿。派伊？

Question

我是Django的新手，尝试在virtualenv中创建Django项目来学习，但在python manage.py make migrations上出现以下错误：

Traceback (most recent call last): File "manage.py", line 21, in main()
File "manage.py", line 17, in main execute_from_command_line(sys.argv)
File
"/home/suraj/Documents/my_projects/django_project/venv/lib/python3.6/site-packages/django/core/management/init.py", line 381, in execute_from_command_line utility.execute()
File
"/home/suraj/Documents/my_projects/django_project/venv/lib/python3.6/site-packages/django/core/management/init.py", line 357, in execute django.setup()
File
"/home/suraj/Documents/my_projects/django_project/venv/lib/python3.6/site-packages/django/init.py", line 24, in setup apps.populate(settings.INSTALLED_APPS)
File
"/home/suraj/Documents/my_projects/django_project/venv/lib/python3.6/site-packages/django/apps/registry.py", line 114, in populate app_config.import_models()
File
"/home/suraj/Documents/my_projects/django_project/venv/lib/python3.6/site-packages/django/apps/config.py", line 211, in import_models self.models_module = import_module(models_module_name)
File
"/home/suraj/Documents/my_projects/django_project/venv/lib/python3.6/importlib/init.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level) File "", line 994, in _gcd_import File "", line 971, in _find_and_load File "", line 955, in _find_and_load_unlocked
File "", line 665, in _load_unlocked File "", line 678, in exec_module File "", line 219, in _call_with_frames_removed
File
"/home/suraj/Documents/my_projects/django_project/web_board/boards/models.py", line 11, in
class Topic(models.Model):
File
"/home/suraj/Documents/my_projects/django_project/web_board/boards/models.py", line 14, in Topic
board = models.ForeignKey(Board, related_name='topics')
TypeError: init() missing 1 required positional argument: 'on_delete'

Answer 1

看起来您正在使用外键创建模型。你知道吗

创建此类模型时，必须指定删除外键表中的记录时要执行的操作。你知道吗

只需添加在模型中使用on_delete参数删除记录时应该发生的事情，就可以了。你知道吗

board = models.ForeignKey(Board, related_name='topics', on_delete=**what_you_want_to_do_when_parent_record_gets_deleted**)

what does on_delete do on Django models?