如何将每种食物添加到领域中自己的食物类别？

Question

我嵌套了 class 这样的：

struct Category {
    let name : String
    let foods : [Food]
}

struct Food {
    let name : String
    let price : Double
}

let categories = [
    Category(name: "Breakfast", foods : [
        Food(name: "Hafta İçi Kahvaltısı", price: 18.0),
        Food(name: "Pazar Kahvaltısı", price: 25.0),
        Food(name: "Diyet Kahvaltı", price: 22.0),
        Food(name: "Köy Kahvaltısı", price: 15.0),
        Food(name: "Ege Kahvaltısı", price: 30.0)]),
    Category(name: "Hamburger", foods : [
        Food(name: "Big TezBurger", price: 26.0),
        Food(name: "TezRoyal", price: 24.0),
        Food(name: "Double TezzBurger", price: 17.0),
        Food(name: "TezChicken", price: 21.0),
        Food(name: "Köfteburger", price: 28.0)])
]

我想要 Realm 数据库中的上述结构。

首先，我使用以下代码在 Realm 中创建了 Category table(class)：

let realm = try! Realm()
var categoryDB = Category()
categoryDB.name = "Breakfasts"
try! realm.write {
     realm.add(categoryDB)
  }

在我创建 Category table 之后，我添加了以下代码以填充每个类别 Food table

categoryDB.name = "Breakfasts"
categoryDB.foods[0].name = "Hafta İçi Kahvaltısı"
categoryDB.foods[0].price = 18.0

categoryDB.name = "Breakfasts"
categoryDB.foods[1].name = "Köy Kahvaltısı"
categoryDB.foods[1].price = 20.0

但我收到类似 Terminating app due to uncaught exception 'RLMException', reason: 'Index 0 is out of bounds (must be less than 0).'

的错误

结论：我需要 Breakfast 类别中的 5 种不同早餐和 Lunch 类别中的 5 种不同食物。我的Categorytable下没有Food列表数据作为foods属性.

link

我的详细领域工作室屏幕

https://youtu.be/WXnxDA15Rho

Answer 1

当您创建 categoryDB 时，它的 foods 是空的。这就是您获得索引越界异常的原因。

您想创建 Food 并将其附加到 categoryDB.foods。

let categoryDB = CategoryDB()

categoryDB.name = "Breakfasts"

let food1 = Food()
food1.name = "Hafta İçi Kahvaltısı"
food1.price = 18.0

let food2 = Food()
food2.name = "Köy Kahvaltısı"
food2.price = 20.0

categoryDB.foods.append(objectsIn: [food1 , food2])

try! realm.write {
    realm.add(categoryDB)
}

如何将每种食物添加到领域中自己的食物类别？

How to add each food to own food category in realm?

realm

ios

swift