ValueError:无法在OneToOneField关系上分配User:issue

Question

OneToOneField我面临一个非常奇怪的问题.我有一个非常简单的模型

class Doctor(models.Model):
    user = models.OneToOneField(User)

问题在于迁移中的方法RunPython.我写了一个取决于0001_initial的0002_addusers迁移,代码如下:

class Migration(migrations.Migration):
    def create_users(apps, schema_editor):
        u = User.objects.create_superuser('admin', 'admin@aaa.com', 'admin')
        u.save()

        du = User.objects.create_user(username='doc01', password='doc01')
        du.save()

def create_doctors(apps, schema_editor):
    Doctor = apps.get_model('custom_user', 'Doctor')
    du = User.objects.get(username='doc01')

    d = Doctor(user=du)
    d.save()

dependencies = [
    ('custom_user', '0001_initial')
]

operations = [
    migrations.RunPython(create_users),
    migrations.RunPython(create_doctors),
]

对我来说真正奇怪的是,这个非常简单的代码在视图中工作,在shell中工作,除了在迁移中工作在任何地方:)

追溯如下:

line 23, in create_doctors
d = Doctor(user=du)
...
ValueError: Cannot assign "<User: doc01>": "Doctor.user" must be a "User" instance.

非常感谢您的支持!

编辑: 我找到了解决方案.我只需要调用RunPython

migrations.RunPython(create_users,create_doctor)

正如Avinash所建议的那样,即使没有在课堂外移动功能.

似乎后续函数必须作为单个RunPython调用的参数调用.

Answer 1

我认为问题出在您的迁移代码中。在 Migration 类外部定义方法，然后从迁移的 RunPython 命令调用它。

在迁移文件中尝试以下代码。这会起作用。

def create_users(apps, schema_editor):
    u = User.objects.create_superuser('admin', 'admin@aaa.com', 'admin')
    u.save()

    du = User.objects.create_user(username='doc01', password='doc01')
    du.save()

def create_doctors(apps, schema_editor):
    Doctor = apps.get_model('custom_user', 'Doctor')
    du = User.objects.get(username='doc01')
    # We can't import the Doctor model directly, But we can create it. Try this - 
    Doctor.objects.create(user=du)

class Migration(migrations.Migration):

    dependencies = [
        ('custom_user', '0001_initial')
    ]

    operations = [
        migrations.RunPython(create_users, create_doctors),
    ]