Swift数据关系

Question

我正在使用新的 swiftData 我试图理解这些关系是如何工作的，我很高兴必须对类进行建模：

我的应用程序上的每个航班都包含许多机组人员，我编写了如下代码所示的关系，但不断收到错误“致命错误：反向关系不存在”

我们应该如何写这个关系：

@Model
class Flight {
    @Attribute(.unique) var flightID: UUID
    var typeOfFlight: String
    var flightDateUTC : Date
    var flightNumber: String?
    
    @Relationship(.cascade) var flightData: FlightData
    @Relationship(.cascade) var flightTime : FlightTime
    @Relationship(.noAction) var aircraft : Aircraft?
    @Relationship(inverse: \CrewModel.name)
    var crews : [CrewModel]? //<-------------------------------
    
    init(flightID: UUID, typeOfFlight: String, flightDateUTC: Date, flightNumber: String? = nil, flightData: FlightData, flightTime: FlightTime, aircraft: Aircraft? = nil, crews: [CrewModel]? = nil) {
        self.flightID = flightID
        self.typeOfFlight = typeOfFlight
        self.flightDateUTC = flightDateUTC
        self.flightNumber = flightNumber
        self.flightData = flightData
        self.flightTime = flightTime
        self.aircraft = aircraft
        self.crews = crews
    }
}


@Model
class CrewModel{
    
    @Attribute(.unique) var id: UUID = UUID()
    @Relationship(.noAction, inverse: \Flight.flightID)
    var name : String?
    var crewID: String?
    var company: String?
    var isMe: Int?
    var email: String?
    var phone: String?
    var score: Int?
    var isPIC: Int?
    var isSIC: Int?
    var dataImage: Data?
    var comment: String?
    
    init(id: UUID, name: String? = nil, crewID: String? = nil, company: String? = nil, isMe: Int? = nil, email: String? = nil, phone: String? = nil, score: Int? = nil, isPIC: Int? = nil, isSIC: Int? = nil, dataImage: Data? = nil, comment: String? = nil) {
        self.id = id
        self.name = name
        self.crewID = crewID
        self.company = company
        self.isMe = isMe
        self.email = email
        self.phone = phone
        self.score = score
        self.isPIC = isPIC
        self.isSIC = isSIC
        self.dataImage = dataImage
        self.comment = comment
    }
}

Answer 1

使用inverse参数时，您只需在一种模型类型中定义关系。的值inverse必须指向模型类型的属性。

在Flight

@Relationship(inverse: \CrewModel.flight) var crews : [CrewModel]?

并在CrewModel

var flight: Flight?