出现以下 fatal error 。
fatal error: 'try!' expression unexpectedly raised an error: Error Domain=io.realm Code=1 "Schema validation failed due to the following errors: - Property 'GearModel.category' declared as origin of linking objects property 'CategoryRepository.gearList' links to type 'CategoryModel'" UserInfo={NSLocalizedDescription=Schema validation failed due to the following errors: - Property 'GearModel.category' declared as origin of linking objects property 'CategoryRepository.gearList' links to type 'CategoryModel', Error Code=1}:
此处的对象模型:齿轮模型仅分配给一个类别
import Foundation
import RealmSwift
class GearModel: Object{
dynamic var gearID = NSUUID().uuidString
dynamic var name = ""
dynamic var manufacturer = ""
dynamic var sortOrder = 0
dynamic var category: CategoryModel?
override class func primaryKey() -> String? {return "gearID"}
}
类别模型:尝试获取分配了类别的所有 GearModel 项目的列表。
import Foundation
import RealmSwift
class CategoryModel: Object{
dynamic var categoryID = NSUUID().uuidString
dynamic var sortOrder = 0
dynamic var name = ""
let gearList = LinkingObjects(fromType: GearModel.self, property: "category")
override class func primaryKey() -> String? {return "categoryID"}
}
Category Repository 类:allCategories() 函数中的“let realm =...”行发生 fatal error
import Foundation
import RealmSwift
class CategoryRepository: CategoryModel{
class func GetGearItemsForCategory(CategoryID: String) -> Results<GearModel>
{
let realm = try! Realm()
var gearItems = realm.objects(GearModel.self)
let predicate = NSPredicate(format: "categoryID = %@", CategoryID)
gearItems = gearItems.filter(predicate)
return gearItems
}
class func GetCountOfGearItems(CategoryID: String) -> Int
{
let realm = try! Realm()
var gearItems = realm.objects(GearModel.self)
let predicate = NSPredicate(format: "categoryID = %@", CategoryID)
gearItems = gearItems.filter(predicate)
return gearItems.count
}
class func AddCategory(CategoryID: String, Name: String, SortOrder: Int){
let realm = try! Realm()
let category = CategoryModel(name: CategoryID, categoryID: Name, sortOrder: SortOrder)
try! realm.write {
realm.add(category)
}
}
class func allCategories() -> Results<CategoryModel> {
let realm = try! Realm()
return realm.objects(CategoryModel.self).sorted(byProperty: "SortOrder")
}
最佳答案
不支持从具有 LinkingObjects
属性的类继承。
Realm 中的 Object 和 List 属性不是协变的,这意味着它们只能指向指定的类,而不能指向该类的子类。这意味着 GearModel.category
无法链接到 CategoryRepository
对象,但是 CategoryRepository
具有正在尝试继承的 gearList
属性列出链接到它的 GearModel
对象。
在您的特定情况下,尚不清楚为什么 CategoryRepository
继承自 CategoryModel
。
关于swift - 使用 LInkingOjbects 的 Realm 在运行时出现 fatal error ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40575321/