AttributeError: 'Query' object has no attribute 'explain_query'

Question

I seem to be receiving an error when I try to start the server or run 'makemigrations'.

Can anybody point out what might be wrong?

I am using Django 4.0.

Traceback (most recent call last):
  File "manage.py", line 24, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\core\management\__init__.py", line 446, in execute_from_command_line
    utility.execute()
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\core\management\__init__.py", line 440, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\core\management\base.py", line 414, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\core\management\base.py", line 460, in execute
    output = self.handle(*args, **options)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\core\management\base.py", line 98, in wrapped
    res = handle_func(*args, **kwargs)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\core\management\commands\makemigrations.py", line 119, in handle
    loader.check_consistent_history(connection)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\migrations\loader.py", line 313, in check_consistent_history
    applied = recorder.applied_migrations()
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\migrations\recorder.py", line 82, in applied_migrations
    return {
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 320, in __iter__
    self._fetch_all()
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 1507, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 57, in __iter__
    results = compiler.execute_sql(
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\sql\compiler.py", line 1348, in execute_sql
    sql, params = self.as_sql()
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38-32\lib\site-packages\sql_server\pyodbc\compiler.py", line 294, in as_sql
    if self.query.explain_query:
AttributeError: 'Query' object has no attribute 'explain_query'

Answer 1

I just hit this snag as well while attempting to upgrade to Django 4. As it turns out, it appears that today django-mssql-backend==2.8.1 is not Django 4 compatible.

It looks like there is an open bug report and patch in place to fix this, though.

Bug Report: https://github.com/ESSolutions/django-mssql-backend/issues/125

Commit / Pull Request: https://github.com/ESSolutions/django-mssql-backend/pull/126

A requirements file tweak might look something like this:

# django-mssql-backend==2.8.1 has a bug that is incompatible with Django 4.0.5
# the below commit directly resolves the conflict and should be removed when mainstreamed
git+https://github.com/ESSolutions/django-mssql-backend.git@b23d305#egg=django-mssql-backend

There may be other incompatibilities that are discovered aside from the explain_query.

Answer 2

I got here searching for:

AttributeError: 'Query' object has no attribute 'explain_query'

While trying to upgrade from django 3.2 to 4.1.2

So in actuality it looks like the answer is to replace?:

    if self.query.explain_query:

With:

    if self.query.explain_info:

see:

• https://github.com/django/django/blob/b7b28c7c189615543218e81319473888bc46d831/django/db/models/sql/compiler.py#L861 ( from main, as of the time of this answer )