マイグレーションを実行できません - ... 'questions'という名前のフィールドがありません

Question

makemigrationsの後にmigrateにしようとすると、Djangoがこのエラーを返す理由を理解しようとしています。私は関連する名前を変更して最後の移行を削除しようとしましたが、何も機能しません。

多分あなたは何が問題なのでしょうか？移行後の

エラー：django.core.exceptions.FieldDoesNotExist: LanguageQuizSitting has no field named 'questions'

Models.py

from django.db import models 
from SolutionsForLanguagesApp import models as sfl_models 
from jsonfield import JSONField 
import random 

class LanguageQuiz(models.Model): 
    name = models.CharField(max_length=40) 
    language = models.OneToOneField(sfl_models.Language) 


class Question(models.Model): 
    language_quiz = models.ForeignKey(LanguageQuiz,related_name='questions') 
    text = models.TextField() 

class Answer(models.Model): 
    question = models.ForeignKey(Question,related_name='answers') 
    text = models.TextField() 
    correct = models.BooleanField() 

class LanguageQuizSitting(models.Model): 
    user = models.OneToOneField(sfl_models.User) 
    quiz = models.OneToOneField(LanguageQuiz) 
    date_opened = models.DateTimeField(auto_created=True) 
    date_closed = models.DateTimeField(null=True) 
    max_questions = models.IntegerField() 

    def load_questions(self): 
     questions = random.sample(self.quiz.questions,self.max_questions) 
     for question in questions: 
      SittingQuestion.objects.create(question=question,sitting=self) 

    def get_next_question(self): 
     q = self.questions.filter(answered=0) 
     if len(q)>0: 
      return q[0] 
     else: 
      return False 

class SittingQuestion(models.Model): 
    sitting = models.ForeignKey(LanguageQuizSitting,related_name='questions',on_delete=models.CASCADE) 
    question = models.ForeignKey(Question, related_name='SittingQuestions') 
    answered = models.BooleanField(default=0) 
    result = models.BooleanField(default=0) 

LASTマイグレーション

class Migration(migrations.Migration): 

    dependencies = [ 
     ('language_tests', '0001_initial'), 
    ] 

    operations = [ 
     migrations.AlterField(
      model_name='question', 
      name='language_quiz', 
      field=models.ForeignKey(related_name='questions', to='language_tests.LanguageQuiz'), 
     ), 
     migrations.AlterField(
      model_name='sittingquestion', 
      name='question', 
      field=models.ForeignKey(related_name='sitting_questions', to='language_tests.Question'), 
     ), 
     migrations.AlterField(
      model_name='sittingquestion', 
      name='sitting', 
      field=models.ForeignKey(related_name='questions', to='language_tests.LanguageQuizSitting'), 
     ), 
    ] 

TRACEBACK：

(venv) C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2>python manage.py migrate 
Operations to perform: 
    Synchronize unmigrated apps: essay, smart_selects, true_false, super_inlines, staticfiles, multichoice, messages, nested_inline, quiz, django_extensions, django_tables2, constance, crispy_forms 
    Apply all migrations: language_tests, database, admin, sessions, auth, contenttypes, SolutionsForLanguagesApp 
Synchronizing apps without migrations: 
    Creating tables... 
    Running deferred SQL... 
    Installing custom SQL... 
Running migrations: 
    Rendering model states... DONE 
    Applying language_tests.0002_auto_20160711_1524...Traceback (most recent call last): 
    File "manage.py", line 10, in <module> 
    execute_from_command_line(sys.argv) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\core\management\__init__.py", line 354, in execute_from_command_line 
    utility.execute() 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\core\management\__init__.py", line 346, in execute 
    self.fetch_command(subcommand).run_from_argv(self.argv) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\core\management\base.py", line 394, in run_from_argv 
    self.execute(*args, **cmd_options) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\core\management\base.py", line 445, in execute 
    output = self.handle(*args, **options) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\core\management\commands\migrate.py", line 222, in handle 
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\migrations\executor.py", line 110, in migrate 
    self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\migrations\executor.py", line 148, in apply_migration 
    state = migration.apply(state, schema_editor) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\migrations\migration.py", line 115, in apply 
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\migrations\operations\fields.py", line 201, in database_forwards 
    schema_editor.alter_field(from_model, from_field, to_field) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\backends\base\schema.py", line 484, in alter_field 
    old_db_params, new_db_params, strict) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\backends\sqlite3\schema.py", line 203, in _alter_field 
    self._remake_table(model, alter_fields=[(old_field, new_field)]) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\backends\sqlite3\schema.py", line 140, in _remake_table 
    self.create_model(temp_model) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\backends\base\schema.py", line 236, in create_model 
    definition, extra_params = self.column_sql(model, field) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\backends\base\schema.py", line 135, in column_sql 
    db_params = field.db_parameters(connection=self.connection) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\fields\related.py", line 2010, in db_parameters 
    return {"type": self.db_type(connection), "check": []} 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\fields\related.py", line 2001, in db_type 
    rel_field = self.related_field 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\fields\related.py", line 1904, in related_field 
    return self.foreign_related_fields[0] 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\fields\related.py", line 1638, in foreign_related_fields 
    return tuple(rhs_field for lhs_field, rhs_field in self.related_fields if rhs_field) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\fields\related.py", line 1625, in related_fields 
    self._related_fields = self.resolve_related_fields() 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\fields\related.py", line 1618, in resolve_related_fields 
    else self.rel.to._meta.get_field(to_field_name)) 
    File "C:\Users\Milano\PycharmProjects\FutileStudio\SolutionsForLanguages_2\venv\lib\site-packages\django\db\models\options.py", line 554, in get_field 
    raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name)) 
django.core.exceptions.FieldDoesNotExist: LanguageQuizSitting has no field named 'questions' 

Answer 1

だから、問題は、次のいずれかです。

questions = random.sample(self.quiz.questions,self.max_questions) 

self.quizはそこに行く：

quiz = models.OneToOneField(LanguageQuiz) 

とquiz.questionsはそこに行く：

class LanguageQuiz(models.Model): 
    name = models.CharField(max_length=40) 
    language = models.OneToOneField(sfl_models.Language) 

問題質問はLanguageQuizには存在しません。