使用多个ManyToManyField时“django.db.utils.DatabaseError：无法添加外键约束”

Question

我在迁移模型时遇到错误。

Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\mysql\connector\django\base.py", line 115,
 in _execute_wrapper
    return method(query, args)
  File "C:\Python34\lib\site-packages\mysql\connector\cursor.py", line 507, in e
xecute
    self._handle_result(self._connection.cmd_query(stmt))
  File "C:\Python34\lib\site-packages\mysql\connector\connection.py", line 722,
in cmd_query
    result = self._handle_result(self._send_cmd(ServerCmd.QUERY, query))
  File "C:\Python34\lib\site-packages\mysql\connector\connection.py", line 640,
in _handle_result
    raise errors.get_exception(packet)
mysql.connector.errors.DatabaseError: 1215 (HY000): Cannot add foreign key const
raint


in cmd_query
    result = self._handle_result(self._send_cmd(ServerCmd.QUERY, query))
  File "C:\Python34\lib\site-packages\mysql\connector\connection.py", line 640,
in _handle_result
    raise errors.get_exception(packet)
django.db.utils.DatabaseError: Cannot add foreign key constraint

请帮我解决这个错误。在此先感谢!!!

以下是我的模特：

类别模型：

class categories(models.Model) :
    id = dbUtils.BigAutoField(primary_key = True)
    name = models.CharField(unique=True, max_length=100)
    description = models.CharField(max_length=500,blank=True)

Feed模型：

class feeds(models.Model) :
    name = models.CharField(max_length=100, blank = True )
    country = models.ManyToManyField(countries,related_name='feedcountry')
    state = models.ManyToManyField(states,related_name='feedstate')
    city = models.ManyToManyField(cities,related_name='feedcity')

feedsMapping模型：

class feedsMapping(models.Model) :
    id = dbUtils.BigAutoField(primary_key=True)
    feeds = dbUtils.BigForeignKey(feeds, related_name='feedmap')
    language = dbUtils.BigForeignKey(languages, related_name='feedmaplanguage')
    categories = models.ManyToManyField(categories,verbose_name='feedmapcategories')
    title = models.CharField(max_length=100)
    country = models.ManyToManyField(countries,related_name='feedmapcountry')
    state = models.ManyToManyField(states,related_name='feedmapstate')
    city = models.ManyToManyField(cities,related_name='feedmapcity')