相关疑难解决方法(0)

做的时候:

DELETE FROM `jobs` WHERE `job_id` =1 LIMIT 1 

它错误:

#1451 - Cannot delete or update a parent row: a foreign key constraint fails 
(paymesomething.advertisers, CONSTRAINT advertisers_ibfk_1 FOREIGN KEY 
(advertiser_id) REFERENCES jobs (advertiser_id))

这是我的表格:

CREATE TABLE IF NOT EXISTS `advertisers` (
  `advertiser_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `password` char(32) NOT NULL,
  `email` varchar(128) NOT NULL,
  `address` varchar(255) NOT NULL,
  `phone` varchar(255) NOT NULL,
  `fax` varchar(255) NOT NULL,
  `session_token` char(30) NOT NULL,
  PRIMARY KEY (`advertiser_id`),
  UNIQUE KEY …

我收到此错误消息:

第40行的错误1217(23000):无法删除或更新父行:外键约束失败

......当我试图放桌子时:

DROP TABLE IF EXISTS `area`;

......定义如下:

CREATE TABLE `area` (
  `area_id` char(3) COLLATE utf8_spanish_ci NOT NULL,
  `nombre_area` varchar(30) COLLATE utf8_spanish_ci NOT NULL,
  `descripcion_area` varchar(100) COLLATE utf8_spanish_ci NOT NULL,
  PRIMARY KEY (`area_id`),
  UNIQUE KEY `nombre_area_UNIQUE` (`nombre_area`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_spanish_ci;

有趣的是,我已经删除了具有外键的架构中的所有其他表area.实际上,除了area表之外,数据库是空的.

如果数据库中没有任何其他对象,它怎么可能有子行？据我所知,InnoDB不允许在其他模式上使用外键,是吗？

(我甚至可以运行RENAME TABLE area TO something_else命令: - ？)

django.db.utils.InternalError：（1050，“表'django_content_type'已经存在”）

我刚刚从我的朋友那里复制了一个项目，当我运行 makemirations 时它运行正常。但对于 -

python3 manage.py migrate 

它给出了这个错误 -

Operations to perform:
  Apply all migrations: admin, auth, balancesheet, contenttypes, dynapp, pandl2, sessions, trialbal2
Running migrations:
  Applying contenttypes.0001_initial...Traceback (most recent call last):
  File "/home/hostbooks/django1/myproject/lib/python3.6/site-packages/django/db/backends/utils.py", line 82, in _execute
    return self.cursor.execute(sql)
  File "/home/hostbooks/django1/myproject/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 74, in execute
    return self.cursor.execute(query, args)
  File "/home/hostbooks/django1/myproject/lib/python3.6/site-packages/pymysql/cursors.py", line 170, in execute
    result = self._query(query)
  File "/home/hostbooks/django1/myproject/lib/python3.6/site-packages/pymysql/cursors.py", line 328, in _query
    conn.query(q)
  File "/home/hostbooks/django1/myproject/lib/python3.6/site-packages/pymysql/connections.py", line 517, in query
    self._affected_rows = self._read_query_result(unbuffered=unbuffered)
  File "/home/hostbooks/django1/myproject/lib/python3.6/site-packages/pymysql/connections.py", line 732, in _read_query_result …