django.db.utils.OperationalError: 3780 引用列和被引用列不兼容

Question

我正在尝试在 Django 中的两个模型之间添加外键关系，但出现此错误。

Notification模特：

class Notification(models.Model):
    ...
    lab_extension = models.ForeignKey(Labs, on_delete=models.CASCADE, null=True, to_field='lab_id')
    ...

Lab型号

class Lab(models.Model):
    ...
    lab_id = models.AutoField(primary_key=True)
    ...

将此外键字段分配给Notification 模型后，我在执行python manage.py migrate 时收到此错误：

django.db.utils.OperationalError: (3780, "Referencing column 'lab_extension_id' and referenced column 'lab_id' in foreign key constraint [constraint name] are incompatible.")

如果我从 Lab 模型中删除 AutoField 并使用默认 id 字段，则此错误可能不会持续存在。但我正处于无法做到这一点的项目中。我还意识到外键字段通常不可为空，但对于这个项目，Notification 模型可能指向也可能不指向 Lab 模型。

SHOW CREATE TABLE notification 给了我这个：

notification_notification, CREATE TABLE `notification_notification` (
  `id` int NOT NULL AUTO_INCREMENT,
  `read` tinyint(1) NOT NULL,
  `message` longtext NOT NULL,
  `user_id` int NOT NULL,
  `category` varchar(2) NOT NULL,
  `created` datetime(6) NOT NULL,
  `question_id` int DEFAULT NULL,
  `submission_id` int DEFAULT NULL,
  `update_request_id` int DEFAULT NULL,
  `lab_extension_id` int DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `notification_notific_user_id_e9d6f5f4_fk_user_mana` (`user_id`),
  KEY `notification_notification_question_id_af1ad55d_fk_qa_question_id` (`question_id`),
  KEY `notification_notific_submission_id_78f78d05_fk_community` (`submission_id`),
  KEY `notification_notific_update_request_id_39cf03ba_fk_community` (`update_request_id`),
  CONSTRAINT `notification_notific_submission_id_78f78d05_fk_community` FOREIGN KEY (`submission_id`) REFERENCES `community_communitysubmission` (`id`),
  CONSTRAINT `notification_notific_update_request_id_39cf03ba_fk_community` FOREIGN KEY (`update_request_id`) REFERENCES `community_submissionupdaterequest` (`id`),
  CONSTRAINT `notification_notific_user_id_e9d6f5f4_fk_user_mana` FOREIGN KEY (`user_id`) REFERENCES `user_manager_user` (`id`),
  CONSTRAINT `notification_notification_question_id_af1ad55d_fk_qa_question_id` FOREIGN KEY (`question_id`) REFERENCES `qa_question` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3241 DEFAULT CHARSET=latin1

SHOW CREATE TABLE lab 给了我这个：

lab, CREATE TABLE `lab` (
  `lab_id` int unsigned NOT NULL AUTO_INCREMENT,
  `user_id` int unsigned NOT NULL,
  `username` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `project_dir` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '/opt/PacketAccess/',
  `lab_model` int unsigned NOT NULL DEFAULT '0',
  `project_name` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `pn_account` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `deployed` int NOT NULL,
  `progress` int NOT NULL,
  `request_time` int NOT NULL,
  `deploy_time` int NOT NULL,
  `destroy_time` int NOT NULL,
  `user_ip` varchar(260) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `status` int NOT NULL DEFAULT '1',
  `labRegion` varchar(10) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT 'EWR1',
  `pn_progress` int NOT NULL,
  `pn_project_id` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT 'n/a',
  `pn_host_name` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT 'unknown',
  `pn_device_id` varchar(255) COLLATE utf8_bin NOT NULL,
  `pn_device_ip` varchar(40) COLLATE utf8_bin NOT NULL,
  `pn_sdn_ip` varchar(40) COLLATE utf8_bin NOT NULL,
  `pn_nfmp_ip` varchar(40) COLLATE utf8_bin NOT NULL,
  `pn_flow_ip` varchar(40) COLLATE utf8_bin NOT NULL,
  `pn_nfmt_ip` varchar(40) COLLATE utf8_bin NOT NULL,
  `pn_nrcx_ip` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '0.0.0.0',
  `pn_nrcs_ip` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '0.0.0.0',
  `pn_elastic_ip` varchar(40) COLLATE utf8_bin NOT NULL,
  `lab_version` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '17.3',
  `lab_tags` varchar(255) COLLATE utf8_bin NOT NULL,
  `user_email` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT 'n/a',
  `voucher_id` int NOT NULL,
  `admin_password` varchar(10) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `oss_password` varchar(10) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `deployed_email` text CHARACTER SET utf8 COLLATE utf8_bin,
  `lab_name` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `customer_lab_ip` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '0.0.0.0',
  `deployment_test` tinyint(1) DEFAULT NULL,
  `ssl_enabled` tinyint(1) DEFAULT NULL,
  `associated_lab_id` varchar(10) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  PRIMARY KEY (`lab_id`)
) ENGINE=InnoDB AUTO_INCREMENT=11995 DEFAULT CHARSET=utf8mb3 COLLATE=utf8_bin

注意：为了保护隐私，我在这篇文章中更改了一些表和字段的名称，所以如果有些名称不一致，请忽略。

Answer 1

这里是探针，

在实验室表中

  `lab_id` int unsigned NOT NULL AUTO_INCREMENT

在通知中

lab_extension_id` int DEFAULT NULL

这些字段不同，不能设置成foreignKeys，将一种类型移到另一种。