Django 3.0.3 IntegrityError FOREIGN KEY 约束在更改数据库时失败

Question

我的数据库中有两个模型，一个“帐户”model（这是一个自定义用户模型）和一个“返回”model。

我的数据库运行良好，直到添加了“返回”model，它与“用户”model 有 ForeignKey 关系，我怀疑这是导致问题的原因。 （每个回报都属于现有用户。在管理面板中，选项框填充了现有用户，所以我认为这工作正常？）

感谢您对此的任何帮助！

错误：

/admin/returns/return/add/ 处的 IntegrityError

FOREIGN KEY 约束失败

Request Method: POST Request URL: http://127.0.0.1:8000/admin/returns/return/add/ Django Version: 3.0.3 Exception Type: IntegrityError Exception Value:

FOREIGN KEY 约束失败

这是我的 Return 应用程序的 models.py：

from django.db import models

from django.contrib.auth import get_user_model
User = get_user_model()

# Create your models here.
class Return(models.Model):
    user = models.ForeignKey(User, related_name="returns", on_delete=models.PROTECT)
    created_at = models.DateTimeField(auto_now=True)
    last_edited = models.DateTimeField(null=True)

    TAX_YEAR_CHOICES = [
    ('2019', '2019'),
    ('2020', '2020'),
    ('2021', '2021'),
    ]

    tax_year_ending = models.CharField(
        choices=TAX_YEAR_CHOICES,
        max_length=4,
        blank=False,
        null=False,
    )

    RETURN_STATUS_CHOICES = [
    ('1', 'In progress'),
    ('2', 'Completed, awaiting review'),
    ('3', 'Completed, under review'),
    ('4', 'Completed, awaiting client action'),
    ('5', 'Submitted to HMRC'),
    ]

    return_status = models.CharField(
        choices=RETURN_STATUS_CHOICES,
        max_length=1,
        default=1,
        blank=False,
        null=False,
    )

这是我的自定义用户 class（也在 settings.py 中设置）：

class Account(AbstractBaseUser):
    email = models.EmailField(verbose_name='email', max_length=60, unique=True) # tells Django this is the unique ID

    #following required for the AbstractBaseUser class
    date_joined = models.DateTimeField(verbose_name='date joined', auto_now_add=True)
    last_login = models.DateTimeField(verbose_name='last login', auto_now=True)
    is_admin = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    is_staff = models.BooleanField(default=False)
    is_superuser = models.BooleanField(default=False)

    #tell django we want to use email as our username field (for logins)
    USERNAME_FIELD = 'email'

    #tells Django to user AccountManager
    objects = AccountManager()

    #tell django which fields are required on registration:
    #REQUIRED_FIELDS = []

    #what to return when we print the Account object
    def __str__(self):
        return self.email

#following required for AbstractBaseUser class
    #does the user have permissions, yes if is_admin
    def has_perm(self, perm, obj=None):
        return self.is_admin

    def has_module_perms(self, app_label):
        return True

这是来自错误日志的发布请求信息：用户

'3'

last_edited_0

'2020-05-03'

last_edited_1

'13:01:23'

tax_year_ending

'2019'

返回状态

'3'

_加上另一个

'保存并添加另一个'

（我已经确认有一个 pk '3' 的用户）

再次感谢，真的很感激。

Answer 1

您需要代表 pk 号记录用户的实例：

User.objects.get(pk=3)