Python TutorialSeries.objects.get（id=1）**导入时，它只会停留在那里。。。没有进一步显示，这就是发生的情况。它只是停留在那里，你需要输入我说的下一个命令。若要解决您的问题，请尝试下面的答案。您的数据库是新的还是在表中插入了任何数据？

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TutorialSeries.objects.get（id=1）**导入时，它只会停留在那里。。。没有进一步显示，这就是发生的情况。它只是停留在那里，你需要输入我说的下一个命令。若要解决您的问题，请尝试下面的答案。您的数据库是新的还是在表中插入了任何数据？此外，您需要删除TutorialSeries模型中的字段tutorial\u类别的

default=1

。错误：main.TutorialSeries.tutorial\u类别：（fields.E321）字段指定on\u delete=SET\u default，但没有默认值。提示：设置默认值，或更改on_delete规则。如果您知道默认教程类别不会被删除，则使用Set_default。因此，一种解决方案是，您可以将继承其他模型的模型作为外键进行注释，执行迁移，向该模型添加数据，然后取消对引用先前迁移模型的模型的注释，等等。然后可以使用default=1。但是，请确保所引用的模型包含一个id在

default

中指定的数据。祝您愉快！谢谢。

    from django.db import models
    from datetime import datetime
    #Create your models here.

    class TutorialCategory(models.Model):
        tutorial_category = models.CharField(max_length=200)
        category_summary = models.CharField(max_length=200)
        category_slug = models.CharField(max_length=200, default=1)

        class Meta:
            #Gives the proper plural name for admin
            verbose_name_plural = "Categories"

        def __str__(self):
            return self.tutorial_category

    class TutorialSeries(models.Model):
        tutorial_series = models.CharField(max_length=200)
        tutorial_category = models.ForeignKey(TutorialCategory, default=1,verbose_name="Category", on_delete=models.SET_DEFAULT)
        series_summary = models.CharField(max_length=200)

        class Meta:
            #Otherwise we get "Tutorial Serie*ss* in admin"
            verbose_name_plural = "Series"

        def __str__(self):
            return self.tutorial_series

    class Tutorial(models.Model):
        tutorial_title = models.CharField(max_length=200)
        tutorial_content = models.TextField()
        tutorial_published = models.DateTimeField("date published", default = datetime.now())
        tutorial_series = models.ForeignKey(TutorialSeries, default=1, verbose_name="Series", on_delete=models.SET_DEFAULT)
        tutorial_slug = models.CharField(max_length=200,default=1)

        def __str__(self):
            return self.tutorial_title

class TutorialSeries(models.Model):
    tutorial_series = models.CharField(max_length=200)
    tutorial_category = models.ForeignKey(TutorialCategory,verbose_name="Category")
    series_summary = models.CharField(max_length=200)

    class Meta:
        #Otherwise we get "Tutorial Serie*ss* in admin"
        verbose_name_plural = "Series"

    def __str__(self):
        return self.tutorial_series

class Tutorial(models.Model):
        tutorial_title = models.CharField(max_length=200)
        tutorial_content = models.TextField()
        tutorial_published = models.DateTimeField("date published", default = datetime.now())
        tutorial_series = models.ForeignKey(TutorialSeries, verbose_name="Series", blank=True, null=True) #<--changes
        tutorial_slug = models.CharField(max_length=200,default=1)

        def __str__(self):
            return self.tutorial_title

python manage.py makemigrations

No changes detected

python manage.py migrate

Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying admin.0003_logentry_add_action_flag_choices... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying auth.0009_alter_user_last_name_max_length... OK
  Applying auth.0010_alter_group_name_max_length... OK
  Applying auth.0011_update_proxy_permissions... OK
  Applying sessions.0001_initial... OK

__init__.py

python manage.py makemigrations
python manage.py migrate

from django.db import models
from datetime import datetime


class TutorialCategory(models.Model):
    tutorial_category = models.CharField(max_length=200)
    category_summary = models.CharField(max_length=200)
    category_slug = models.CharField(max_length=200)

    class Meta:
        verbose_name_plural = "Categories"

    def __str__(self):
        return self.tutorial_category

class TutorialSeries(models.Model):
    tutorial_series = models.CharField(max_length=200)
    tutorial_category = models.ForeignKey(TutorialCategory, verbose_name="Category", on_delete=models.CASCADE, blank=True, null=True)
    series_summary = models.CharField(max_length=200)

    class Meta:
        verbose_name_plural = "Series"

    def __str__(self):
        return self.tutorial_series

class Tutorial(models.Model):
    tutorial_title = models.CharField(max_length=200)
    tutorial_content = models.TextField()
    tutorial_published = models.DateTimeField('date published', default=datetime.now)

    tutorial_series = models.ForeignKey(TutorialSeries, verbose_name="Series", on_delete=models.CASCADE, blank=True, null=True)
    tutorial_slug = models.CharField(max_length=200, default=1)

    def __str__(self):
        return self.tutorial_title