复合主键领域/交换

Question

我是快速入门的新手。我想做一个复合主键，当我尝试这样的事情时：

class DbLocation : Object {
 dynamic var id = 0
 dynamic var tourId = 0

 dynamic var uuid : String  {
    return "\(id)\(tourId)"
 }

 override static func primaryKey() -> String? {
    return "uuid"
 }
}

我收到此错误：对象’DbLocation’上不存在’主键属性’uuid’

任何人都可以通过示例为我提供帮助，该示例如何创建复合主键？

Answer 1

对于1.0.1+领域：

class DbLocation: Object{
    dynamic var id = 0
    dynamic var tourId = 0
    dynamic var compoundKey = ""

    override static func primaryKey() -> String? {
        return "compoundKey"
    }

    func setup(id: Int, tourId: Int){
        self.id = id
        self.tourId = tourId
        self.compoundKey = compoundKeyValue()
    }

    func compoundKeyValue() -> String {
        return "\(id)\(tourId)"
    }
}

用法示例：

let location = DbLocation()
location.setup(id: 0, tourId: 1) 
print(location.compoundKey) // "01"

当然，你可以玩弄各种使用didSet上的听众id和tourId，以确保compoundKey才能正确重写每一个值换衣服的时间。

对于pre-1.0.1领域：

class DbLocation: Object {
    dynamic var id = 0
    dynamic var tourId = 0

    func setCompoundID(id: Int) {
        self.id = id
        compoundKey = compoundKeyValue()
    }

    func setCompoundTourId(tourId: Int) {
        self.tourId = tourId
        compoundKey = compoundKeyValue()
    }

    dynamic lazy var compoundKey: String = self.compoundKeyValue()

    override static func primaryKey() -> String? {
        return "compoundKey"
    }

    func compoundKeyValue() -> String {
        return "\(id)\(tourId)"
    }
}

自定义设置器确保compoundKey始终处于更新状态，惰性关键字确保您第一次访问它时，它将从您已设置的内容中派生。

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