复合主键领域/ swift

Posted 2021-04-04

我是快速和领域的新手。我想制作一个复合主键，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'

任何人都可以帮我解决如何创建复合主键的示例？

答案

这应该给你答案：

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setter确保复合键始终更新，懒惰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出来。

有关此主题的更多信息，请参阅this thread，此问题一直存在争议。

另一答案

简单地创建一个新属性，其值设置为您希望为复合主键的其他属性。

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

        override static func primaryKey() -> String? {
                return "compoundKey"
            }
        }
    let location = DbLocation()
    location.tourId = 1
    location.id = 5
    location.compoundKey = "(id) (tourId)"

另一答案

对于Swift和Realm的最新版本，我会做这样的事情。

dynamic private var compoundKey: String = ""

required convenience init?(map: Map) {
  self.init()
  if let firstValue = map.JSON["firstValue"] as? String,
    let secondValue = map.JSON["secondValue"] as? Int {
    compoundKey = firstValue + "|someStringToDistinguish|" + "(secondValue)"
  }
}

另一答案

你需要从你的对象中返回一个属性

这是示例代码

class FoodModel:Object
{
    dynamic var name = ""
    dynamic var _id  = ""


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

请注意，_id在模型中是var