ios - Realm 迁移一对多

Question

我需要有关迁移的帮助。

我有这个模型：

class Item: Object {
    @objc dynamic var title: String = ""
    @objc dynamic var done: Bool = false
}

新的迁移有两种模式：

class Item: Object {
    @objc dynamic var title: String = ""
    @objc dynamic var done: Bool = false
    let category = LinkingObjects(fromType: Category.self, property: "items")
}

class Category: Object {
    @objc dynamic var id = NSUUID().uuidString
    @objc dynamic var name: String = ""
    var items = List<Item>()

    override class func primaryKey() -> String {
        return "id"
    }
}

我们无法为新商品创建新的类别，而最后的商品为孤立商品。
我必须创建一个带有“无类别”的新类别并在其中添加旧项目。

我尝试过，但没有成功：

private func zeroToOne(_ migration: Migration, _ oldSchemaVersion: UInt64) -> Void {        
        let category = Category()
        category.name = "No Category"        

        migration.enumerateObjects(ofType: Item.className()) { oldObject, newObject in
            let item = Item()
            item.title = newObject?["title"] as! String
            item.done = newObject?["done"] as! Bool
            category.items.append(item)
        }
        print("and migration")
    }

var configuration: Realm.Configuration {
        let config = Realm.Configuration(schemaVersion: 2, migrationBlock: { (migration, oldVersion) in
            if oldVersion < 3 {
                self.zeroToOne(migration, oldVersion)
            }
        })
        Realm.Configuration.defaultConfiguration = config
        return config
    }

private func initRealm() {
        do {
            self.realm = try Realm(configuration: configuration)
        } catch let error {
            print(error.localizedDescription)
            fatalError("Doenst work Realm")
        }
    }

预先感谢您的帮助，谢谢:)

Answer 1

我用它工作了！

 private func zeroToOne(_ migration: Migration, _ oldSchemaVersion: UInt64) -> Void {
        let category = migration.create(Category.className())
        category["name"] = "No Category"
        category["id"] = NSUUID().uuidString
        migration.enumerateObjects(ofType: Item.className()) { oldObject, newObject in
            if let items = category["items"] as? List<MigrationObject>, let item = newObject {
                items.append(item)
            }
        }
    }