class HeroInfo(models.Model):    # 英雄名    hname = models.CharField(max_length=20)    # 性别    hgender = models.BooleanField(default=False)    # 备注    hcomment = models.CharField(max_length=200)    # 外键    hbook = models.ForeignKey('BookInfo')    # 删除标记    isDelete = models.BooleanField(default=False)

创建迁移文件时报错：

报错环境 python=3.6，django=2.2，PyMySQL=0.9.3

TypeError: __init__() missing 1 required positional argument: 'on_delete'

原因：

django2.0之后定义外键时需指定'on_delete'参数值。

详见django官方文档：

 PS：

django2.1以后不再支持mysql5.5，python manage.py migrate时会报错：

raise MigrationSchemaMissing("Unable to create the django_migrations table (%s)" % exc)django.db.migrations.exceptions.MigrationSchemaMissing: Unable to create the django_migrations table ((1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(6) NOT NULL)'at line 1"))

使用mysql5.7即可。