我刚刚从SQLite3迁移到了Postgres 12（使用pgloader）。

我无法删除某些模型对象，因为还有其他引用它的模型对象。

但是，我非常确定我的模型对象在引用模型对象中设置了“ on_delete = models.CASCADE”（在我的Django代码的models.py中）。

所以我得到了Postgres生成的错误：

...
django.db.utils.IntegrityError: update or delete on table "app_reply" violates foreign key constraint "app_replyimage_reply_id_fkey" on table "app_replyimage"
DetaIL:  Key (id)=(SRB6Nf98) is still referenced from table "app_replyimage".

有没有一种方法（希望不用手动在Postgres中编辑表模式）来解决这个问题？

编辑：在下面添加一些代码...

models.py

class ReplyImage(models.Model):
    id = models.CharField(default = make_id(),unique = True,primary_key = True,max_length = 8)
    
    file = models.ImageField(upload_to = customer_images_directory_path)
    
    reply = models.ForeignKey(Reply,on_delete = models.CASCADE,related_name = 'reply_images')
    
    #Meta
    created = models.DateTimeField(auto_now_add = True)
    updated = models.DateTimeField(auto_now = True)
    created_by = models.ForeignKey(User,related_name = '+',null = True)
    updated_by = models.ForeignKey(User,null = True)
    
    def __str__(self):
        return str(self.id)
    
    def delete(self,*args,**kwargs):
        self.file.delete()
        super(ReplyImage,self).delete(*args,**kwargs)

@receiver(post_delete,sender = ReplyImage)
def reply_image_delete(sender,instance,**kwargs):
    instance.file.delete()

这是引用的模型，回复：

class Reply(models.Model):
    id = models.CharField(default = make_id(),max_length = 8)
    
    #Content
    content = models.CharField(max_length = 560,blank = True,null = True)
    replies = GenericRelation('self')
    link = models.ForeignKey(Link,on_delete = models.SET_NULL,related_name = 'reply',null = True)
    
    #Drip
    drip_interval_quantity = models.IntegerField(default = 0,null = True) #Custom quantity
    drip_interval_calendar_unit = models.CharField(default = 'minute',max_length = 6,choices = DRIP_INTERVAL_CALENDAR_UNIT_CHOICES,null = True) #Custom calendar unit
    
    post_datetime = models.DateTimeField(blank = True,null = True) #Post datetime
    
    #Twitter API
    self_status_id_str = models.CharField(max_length = 19,null = True,blank = True) #status_id_str of self
    in_reply_to_status_id_str = models.CharField(max_length = 19,blank = True) #status_id_str of tweet replied to
    
    #Meta
    created = models.DateTimeField(auto_now_add = True)
    updated = models.DateTimeField(auto_now = True)
    created_by = models.ForeignKey(User,null = True)
    
    #Mandatory fields for generic relation
    content_type = models.ForeignKey(ContentType,on_delete = models.CASCADE)
    object_id = models.CharField(default = make_id(),max_length = 8)
    content_object = GenericForeignKey()
    
    customer = models.ForeignKey(Customer,related_name = 'postreplies')
    
    def delete(self,**kwargs):
        if self.reply_images.all():
            for i in self.reply_images.all():
                i.delete()
        
        if self.link:
            self.link.delete()
        
        super(Reply,**kwargs)
    
    def __str__(self):
        return self.content

@receiver(post_save,sender = Reply)
def reply_model_save(sender,**kwargs):
    if kwargs['raw']:
        return
    
    recursive_reply_save_mock_post(instance)

@receiver(post_delete,sender = Reply)
def reply_model_delete(sender,**kwargs):
    if instance.reply_images.all():
        for i in instance.reply_images.all():
            i.delete()

views.py

...
post.replies.all().delete()
...

（我重新定义了delete（）方法，还添加了post_delete（）信号，但我认为它们不应该影响任何东西，因为它与SQLite完美配合。）

出了什么问题？

编辑2：

Postgres表架构

                       Table "public.app_replyimage"
    Column     |           Type           | Collation | Nullable | Default
---------------+--------------------------+-----------+----------+---------
 file          | text                     |           |          |
 created       | timestamp with time zone |           |          |
 updated       | timestamp with time zone |           |          |
 created_by_id | bigint                   |           |          |
 reply_id      | text                     |           |          |
 updated_by_id | bigint                   |           |          |
 id            | text                     |           | not null |
Indexes:
    "idx_85696_sqlite_autoindex_app_replyimage_1" PRIMARY KEY,btree (id)
    "idx_85696_app_replyimage_created_by_id_a5974d1f" btree (created_by_id)
    "idx_85696_app_replyimage_reply_id_7a8aff2c" btree (reply_id)
    "idx_85696_app_replyimage_updated_by_id_d73f7446" btree (updated_by_id)
Foreign-key constraints:
    "app_replyimage_created_by_id_fkey" FOREIGN KEY (created_by_id) REFERENCES auth_user(id)
    "app_replyimage_reply_id_fkey" FOREIGN KEY (reply_id) REFERENCES app_reply(id)
    "app_replyimage_updated_by_id_fkey" FOREIGN KEY (updated_by_id) REFERENCES auth_user(id)