python - Django 运行余额/累计余额

Question

我有一个具有计算余额(运行余额/累计余额)功能的交易模型，但余额输出作为查询集返回。

<QuerySet [{'id': 1, 'cumsum': -9.0}, {'id': 2, 'cumsum':-16.0},{'id': 3, 'cumsum': -21.0}]>

如何修复我的函数，使余额只显示 10 月 16 日为 -9.00，10 月 18 日为 -16.00，然后 10 月 20 日为 -21.00 的数字。提前谢谢你。

模型.py

class Transaction(models.Model):
    transaction_date = models.DateField()
    account_nickname = models.ForeignKey(Accounts, on_delete=models.CASCADE)
    amount = models.FloatField()

    @property
    def balance(self):
        return Transaction.objects.annotate(cumsum=Func(Sum('amount'),template='%(expressions)s OVER (ORDER BY %(order_by)s)',order_by="id")).values('id', 'cumsum').order_by('id', 'cumsum')

View .py

def index(request):
    all_transactions = Transaction.objects.all()
    context = {
        "transactions": all_transactions
    }
    return render(request,'pages/index.html', context)

index.html

        {% for each_transaction in transactions %}
        <tr>
            <td>{{each_transaction.transaction_date}}</td>
            <td>{{each_transaction.account_nickname}}</td>
            <td>{{each_transaction.amount}}</td>
            <td>{{each_transaction.balance}}</td>
        </tr>
        {% endfor %}

输出:

Answer 1

首先移除你的@property balance函数

然后在 views.py

def index(request):
    all_transactions = Transaction.objects.annotate(cumsum=Func(Sum('amount'),template='%(expressions)s OVER (ORDER BY %(order_by)s)',order_by="id"))
    context = {
        "transactions": all_transactions
    }
    return render(request,'pages/index.html', context)

然后在你的 index.html

{% for each_transaction in transactions %}
<tr>
    <td>{{each_transaction.transaction_date}}</td>
    <td>{{each_transaction.account_nickname}}</td>
    <td>{{each_transaction.amount}}</td>
    <td>{{each_transaction.cumsum}}</td>
</tr>
{% endfor %}