Джанго - УНИКАЛЬНЫЙ ПРЕПЯТСТВОВАЛИ FAILED ошибка

Question

Это то, что мой models.py выглядит следующим образом:

from django.db import models 
    from django.core.validators import RegexValidator 

    # Create your models here. 
    class Customer(models.Model): 
     customer_id = models.AutoField(primary_key=True,unique=True) 
     full_name = models.CharField(max_length=50) 
     user_email = models.EmailField(max_length=50) 
     user_pass = models.CharField(max_length=30) 

     def __str__(self): 
      return "%s" % self.full_name 

    class CustomerDetail(models.Model): 
     phone_regex = RegexValidator(regex = r'^\d{10}$', message = "Invalid format! E.g. 4088385778") 
     date_regex = RegexValidator(regex = r'\d{2}[-/]\d{2}[-/]\d{2}', message = "Invalid format! E.g. 05/16/91") 

     address = models.CharField(max_length=100) 
     date_of_birth = models.CharField(validators = [date_regex], max_length = 10, blank = True) 
     company = models.CharField(max_length=30) 
     home_phone = models.CharField(validators = [phone_regex], max_length = 10, blank = True) 
     work_phone = models.CharField(validators = [phone_regex], max_length = 10, blank = True) 
     customer_id = models.ForeignKey(Customer, on_delete=models.CASCADE) 

Я добавил customer_id к Customer после того как я добавил же в CustomerDetail в качестве внешнего ключа. Почему я все еще получаю эту ошибку после запуска миграции, даже после того, как я добавил unique=True в customer_id?

Error: 
     Rendering model states... DONE 
     Applying newuser.0003_auto_20160823_0128...Traceback (most recent call last): 
      File "/home/krag91/Documents/djangodev/virtualenv /lib/python3.5/site-packages/django/db/backends/utils.py", line 64, in  execute 
    return self.cursor.execute(sql, params) 
      File "/home/krag91/Documents/djangodev/virtualenv /lib/python3.5/site-packages/django/db/backends/sqlite3/base.py", line 337, in execute 
    return Database.Cursor.execute(self, query, params) 
     sqlite3.IntegrityError: UNIQUE constraint failed:  newuser_customer.customer_id 
The above exception was the direct cause of the following exception: 

Traceback (most recent call last): 
    File "manage.py", line 22, in <module> 
    execute_from_command_line(sys.argv) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line utility.execute() 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/core/management/__init__.py", line 359, in execute 
    self.fetch_command(subcommand).run_from_argv(self.argv) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/core/management/base.py", line 305, in run_from_argv 
    self.execute(*args, **cmd_options) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/core/management/base.py", line 356, in execute 
    output = self.handle(*args, **options) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 202, in handle 
    targets, plan, fake=fake, fake_initial=fake_initial 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/migrations/executor.py", line 97, in migrate 
    state = self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/migrations/executor.py", line 132, in _migrate_all_forwards 
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/migrations/executor.py", line 237, in apply_migration 
    state = migration.apply(state, schema_editor) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/migrations/migration.py", line 129, in apply 
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/migrations/operations/fields.py", line 84, in database_forwards 
    field, 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/sqlite3/schema.py", line 231, in add_field 
    self._remake_table(model, create_fields=[field]) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/sqlite3/schema.py", line 199, in _remake_table 
    self.quote_name(model._meta.db_table), 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 112, in execute 
    cursor.execute(sql, params) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/utils.py", line 79, in execute 
    return super(CursorDebugWrapper, self).execute(sql, params) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/utils.py", line 64, in execute 
    return self.cursor.execute(sql, params) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/utils.py", line 94, in __exit__ 
    six.reraise(dj_exc_type, dj_exc_value, traceback) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/utils/six.py", line 685, in reraise 
    raise value.with_traceback(tb) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/utils.py", line 64, in execute 
    return self.cursor.execute(sql, params) 
    File "/home/krag91/Documents/djangodev/virtualenv/lib/python3.5/site-packages/django/db/backends/sqlite3/base.py", line 337, in execute 
    return Database.Cursor.execute(self, query, params) 
django.db.utils.IntegrityError: UNIQUE constraint failed: newuser_customer.customer_id 

Answer 1

Кажется, что вы - already having some objects as per old model definitions. By default django creates a field named as id to every model in database. Доступ к нему можно получить с помощью modelName.id.

В вашем случае я предполагаю, что произошло то, что у вас есть некоторые объекты в базе данных с customer.id как первичные, как первичный ключ. Поэтому, когда вы изменили модели и применяемые миграции, existing objects are checked and another unique field is tried to added as a primary key. Здесь обходным путем является удаление всех существующих объектов после удаления поля customer_id, а затем попытка воссоздания поля и выполнения миграции.

HTH