Cannot query "admin": Must be "ChatMessage" instance in Django

Question

In View Function

it can show this error

Request Method:GETRequest URL:http://127.0.0.1:8000/inbox/Django Version:4.2.25Exception Type:ValueErrorException Value:Cannot query "admin": Must be "ChatMessage" instance.Exception Location:D:\Socialmedia\.venv\lib\site-packages\django\db\models\sql\query.py, line 1253, in check_query_object_typeRaised during:core.views.messages.inboxPython Executable:D:\Socialmedia\.venv\Scripts\python.exePython Version:3.9.13Python Path:['D:\\Socialmedia', 'C:\\Users\\ER-RPJ\\AppData\\Local\\Programs\\Python\\Python39\\python39.zip', 'C:\\Users\\ER-RPJ\\AppData\\Local\\Programs\\Python\\Python39\\DLLs', 'C:\\Users\\ER-RPJ\\AppData\\Local\\Programs\\Python\\Python39\\lib', 'C:\\Users\\ER-RPJ\\AppData\\Local\\Programs\\Python\\Python39', 'D:\\Socialmedia\\.venv', 'D:\\Socialmedia\\.venv\\lib\\site-packages']

def inbox(request):
 if request.user.is_authenticated:
 user_id = request.user
 chat_messages = ChatMessage.objects.filter(
 id__in=Subquery(
 User.objects.filter(
 Q(chat_sender__chat_receiver=user_id) |
 Q(chat_receiver__chat_sender=user_id)
 ).distinct().annotate(
 last_msg=Subquery(
 ChatMessage.objects.filter(
 Q(sender=OuterRef('id'), receiver=user_id) |
 Q(receiver=OuterRef('id'), sender=user_id)
 ).order_by('-id')[:1].values_list('id', flat=True)
 )
 ).values_list('last_msg', flat=True).order_by('-id')
 )
 ).order_by('-id')
 context = {
 'chat_messages': chat_messages,
 }
 return render(request, 'chat/inbox.html', context)

In My model

class ChatMessage(models.Model):
 user = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True, related_name='chat_user')
 chat_sender = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True, related_name='chat_sender')
 chat_receiver = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True, related_name='chat_receiver')
 message = models.TextField()
 is_read = models.BooleanField(default=False)
 date = models.DateTimeField(auto_now_add=True)
 mid=ShortUUIDField(length=7,max_length=25,alphabet='abcdefghijklmnopqrstuvwxyz')
 # def __str__(self):
 # return self.user
 class Meta:
 verbose_name_plural = 'Chat messages'

• jsotola: please add a focused, answerable question to your post
• willeM_ Van Onsem: What database do you use?

Answer 1

You probably can simplify this to:

def inbox(request):
 if request.user.is_authenticated:
 user_id = request.user
 chat_messages = ChatMessage.objects.filter(
 Q(chat_sender=user_id) | Q(chat_receiver=user_id),
 ~Exists(ChatMessage.objects.filter(
 Q(chat_sender=OuterRef('chat_sender'), chat_receiver=OuterRef('chat_receiver')) |
 Q(chat_sender=OuterRef('chat_receiver'), chat_receiver=OuterRef('chat_sender')),
 date__gt=OuterRef('date')
 ))
 ).order_by('-date')
 context = {
 'chat_messages': chat_messages,
 }
 return render(request, 'chat/inbox.html', context)