views.py中的AttributeError：type对象'Transaction'没有属性'objects'

Question

I have run into an issue using Django. I am creating a finance app which tracks deposits and withdrawals.Unfourtanently I have run into an issue using models. Here is the relevant code

Views.py

from django.shortcuts import render
from .models import Transaction

# Create your views here.
class Transaction:
    def __init__(self, name, description, location, amount):
        self.name = name
        self.description = description
        self.location = location
        self.amount = amount    

def sum(totals):
    sum = 0
    for i in range(len(totals)):
        if totals[i].name.lower() == 'deposit':
            sum += totals[i].amount
        else:
            sum -= totals[i].amount
    return sum


#transactions = [
#   Transaction('Deposit', 'Allowance', 'Home', 25.00),
#   Transaction('Withdrawl', 'Food', 'Bar Burrito', 11.90),
#   Transaction('Withdrawl', 'Snacks', 'Dollarama', 5.71)
#]



def index(request):
    transactions = Transaction.objects.all()
    balance = sum(transactions)
    return render(request, 'index.html', {'transactions':transactions,  'balance': balance})

Models.py

from django.db import models

# Create your models here.
class Transaction(models.Model):
    name = models.CharField(max_length = 100)
    description = models.CharField(max_length = 100)
    location = models.CharField(max_length = 100)
    amount = models.DecimalField(max_digits = 10, decimal_places = 2)

    def __str__(self):
        return self.name

admin.py

from django.contrib import admin
from .models import Transaction

# Register your models here.
admin.site.register(Transaction)

Let me know if there is any other code you need to look at and thanks in advance

Answer 1

You don't need a second Transaction class in your views. It is shadowing the Transaction model/class imported from your model. Remove it!

More so, you also don't need a custom sum function, use the builtin sum :

def index(request):
    transactions = Transaction.objects.all()
    balance = sum(t.amount if t.name=='deposit' else -t.amount for t in transactions)
    ...

Answer 2

The Transaction class that you have in your views.py file shadows your Transaction model.

Transaction in views.py file is a simple python class (not a Django model), to fix your issue, you need to remove it from views.py