我正在使用 python 3.4 在 django 1.8 中编写一个应用程序，我遇到了使用 MySQL 作为数据库后端的问题，这让我完全被难住了。

当我从一个新数据库开始并调用 ./manage.py migrate(或 syncdb)并尝试创建初始数据库时，我得到以下回溯:

(virtualenv)~/projects/projmoj (master ✘)✹✭ ᐅ ./manage.py migrate
Operations to perform:
  Synchronize unmigrated apps: allauth, rest_framework, registration, rest_auth, projmoj, messages, project, staticfiles
  Apply all migrations: contenttypes, sites, sessions, task, auth, admin, authtoken, static_precompiler, account
Synchronizing apps without migrations:
  Creating tables...
    Creating table project_project
    Creating table project_membership
    Running deferred SQL...
Traceback (most recent call last):
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/django/db/backends/mysql/base.py", line 124, in execute
    return self.cursor.execute(query, args)
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/MySQLdb/cursors.py", line 220, in execute
    self.errorhandler(self, exc, value)
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorvalue
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/MySQLdb/cursors.py", line 209, in execute
    r = self._query(query)
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/MySQLdb/cursors.py", line 371, in _query
    rowcount = self._do_query(q)
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/MySQLdb/cursors.py", line 335, in _do_query
    db.query(q)
  File "/home/tobbe/projects/projmoj/virtualenv/lib/python3.4/site-packages/MySQLdb/connections.py", line 280, in query
    _mysql.connection.query(self, query)
_mysql_exceptions.OperationalError: (1005, 'Can\'t create table `tasks`.`#sql-1c32_9` (errno: 150 "Foreign key constraint is incorrectly formed")')

当我在网络托管服务上执行相同的操作时会发生此错误，它可以工作，但是在托管服务和本地主机上都使用 sqlite。

我没有迁移，这些是我的模型:

class Project(models.Model):
  name = models.CharField(max_length = 32) 
  description = models.TextField(null=True, blank=True)
  creation_date = models.DateTimeField(auto_now_add=True)

  def get_owner(self):
    return self.members.filter(status=OWNER).first().user

  def get_membership(self, user):
    return self.members.filter(user=user).first()

  def __str__(self):
    return str(self.name) + " - by " + str(self.get_owner().username)

class Membership(models.Model):
  user = models.ForeignKey(User, related_name='joined_projects')
  project = models.ForeignKey(Project, related_name='members')
  status = models.PositiveSmallIntegerField(choices=MEMBER_STATUS)
  join_date = models.DateTimeField(auto_now_add=True)

  def __str__(self):
    return str(self.user.username)

class Sprint(models.Model):
  name = models.CharField(max_length = 32, null=True, blank=True)
  start_date = models.DateTimeField()
  due_date = models.DateTimeField(null=True, blank=True)
  project = models.ForeignKey(Project, related_name='sprints')
  status = models.PositiveSmallIntegerField(choices=SPRINT_STATUS, default=PLANNING)

  def __str__(self):
    return str(self.name) + " - " + str(self.project)

class Category(models.Model):
  name = models.CharField(max_length = 32) 
  project = models.ForeignKey(Project, related_name='categories')

  def __str__(self):
    return str(self.name) + " - " + str(self.project)

class Goal(models.Model):
  name = models.CharField(max_length = 32) 
  description = models.TextField(null=True, blank=True)
  project = models.ForeignKey(Project, related_name='goals')
  completion = models.PositiveSmallIntegerField(choices=COMPLETION, default=NOT_COMPLETED)

  def __str__(self):
    return str(self.name) + " - " + str(self.project)

class Task(models.Model):
  name = models.CharField(max_length = 64)
  description = models.TextField(null=True, blank=True)
  project = models.ForeignKey(Project, related_name='tasks')
  category = models.ForeignKey(Category, related_name='tasks', null=True, blank=True)
  goal = models.ForeignKey(Goal, related_name='tasks', null=True, blank=True)
  creation_date = models.DateTimeField(auto_now_add=True)
  sprint = models.ForeignKey(Sprint, related_name='tasks', null=True, blank=True)
  status = models.PositiveSmallIntegerField(choices=TASK_STATUS, default=WAITING)
  dedicated_hours = models.DecimalField(max_digits=6, decimal_places=2, null=True, blank=True)
  assigned_worker = models.ForeignKey(User, null=True, blank=True)
  priority = models.PositiveSmallIntegerField(choices=PRIORITY, default=NORMAL)

  def __str__(self):
    return str(self.name) + " - " + str(self.project)

class HourReport(models.Model):
  task = models.ForeignKey(Task, related_name='hour_reports')
  worker = models.ForeignKey(User, related_name='hour_reports')
  hours_spent = models.DecimalField(max_digits=6, decimal_places=2)
  date = models.DateTimeField(auto_now_add=True)

  def __str__(self):
    return str(self.hours_spent) + " on " + str(self.task)

我的数据库设置:

DATABASES = { 
  'default': {
      'ENGINE': 'django.db.backends.mysql',
      'NAME': 'tasks',
      'USER': 'root',
      'PASSWORD': 'mysqlmysql',
      'HOST': 'localhost',
  }
}

版本等:

• Django 1.8
• python 3.4
• 默认存储引擎:InnoDB
• Mysql客户端1.3.6
• 服务器:Amazon RDS 上的 MySQL 5.5.42(在虚拟主机上)
• 服务器:10.0.21-MariaDB-log MariaDB 服务器(本地主机)

当谷歌搜索时，这个错误似乎经常出现在人们填充他们的手动 SQL 代码时，但我是通过 django 自动完成的。

有什么想法吗？

最佳答案

日志告诉您您还没有为您的项目 应用程序创建迁移。您应该在运行迁移之前为应用程序创建迁移。

./manage.py makemigrations project
./manage.py migrate

由于它是一个新数据库，您最好在创建和应用迁移之前完全重置它，否则您将不得不手动处理其当前的不一致状态。

关于python - 由于 errno : 150 "Foreign key constraint is incorrectly formed"，Django 1.8 应用程序初始迁移神秘失败，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32573600/