Swift 具有一对多关系的求和值

我有两个实体交易和账户。一个账户有许多交易。我使用这段代码计算所有交易（所有账户）的总和：

但我不知道如何对属于每个账户的交易进行汇总。我有一个ForEach，它显示每个账户，我想把它们的交易总额也放进去。有人能给我指一下正确的方向吗

编辑： 以下是核心数据模型：

Account+CoreDataProperties.swift
    
@NSManaged public var bank: String?
@NSManaged public var name: String?
@NSManaged public var iban: String?
@NSManaged public var city: String?
@NSManaged public var postal: String?
@NSManaged public var street: String?
@NSManaged public var country: String?
@NSManaged public var transaction: NSSet?
    
public var wrappedName: String 
   name ?? "Unknown Account" 
}

//...

Transaction+CoreDataProperties.swift

@NSManaged public var category: String?
    @NSManaged public var comment: String?
    @NSManaged public var date: Date?
    @NSManaged public var name: String?
    @NSManaged public var value: Double
    @NSManaged public var account: Account?

public var wrappedName: String {
        name ?? "Unknown Transaction"
    }

    public var wrappedComment: String {
        comment ?? "Unknown Comment"
    }

//...

---

似乎每个账户都记录了其所有交易；遍历帐户并对其交易进行求和

for account in accounts {
    let sumForThisAccount = account.transactions.map { $0.value }.reduce(0, +)
}

---

如果您展示了

交易

和

账户

的模型，这会有所帮助，因为如果不是这样，代码就太深奥了。完成后，我希望helpsWorks完美无瑕！非常感谢。

for account in accounts {
    let sumForThisAccount = account.transactions.map { $0.value }.reduce(0, +)
}