與非標準化數據域遷移

Question

比方說，你有一個像

class Person: Object { 
    var dynamic firstName: String = "" 
    var dynamic lastName: String = "" 
} 

境界對象現在，我想升級數據庫，並提取出姓氏進入一個新的類像這樣

class LastName: Object { 
    var dynamic sirName: String = "" 

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

class Person: Object { 
    var dynamic firstName: String = "" 
    var dynamic lastName: LastName! 
} 

什麼遷移看起來像什麼？我嘗試了一個簡單的遷移，但這可能會導致具有相同primaryKey的多個LastName對象。

Answer 1

在你AppDelegate的didFinishLaunchingWithOptions：

let configuration = Realm.Configuration(
    schemaVersion: 1, //This must be larger than the previous schemaVersion 
    migrationBlock: { migration, oldSchemaVersion in 
     if oldSchemaVersion < 1 { 
      migration.enumerate(Person.className()) { oldObject, newObject in 
       let lastName = oldObject!["lastName"] as! String 
       let newValue: [String: String] = ["sirName": lastName] 
       let createdObject = migration.create(LastName.className(), value: newValue) 
       newObject!["lastName"] = createdObject 
      } 
     } 
}) 

Realm.Configuration.defaultConfiguration = configuration // Set the new configuration as default 

let realm = try! Realm() // Open the default realm to perform the migration 

要添加，這現在有primaryKey作品以及與模型看起來像這樣：

class Person: Object { 
    dynamic var firstName: String = "" 
    dynamic var lastName: LastName! 
} 

class LastName: Object { 
    dynamic var sirName: String = "" 

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

但這種遷移將無法正常工作如果由於primaryKey是每個對象的唯一標識符而存在lastName的重複項，則要麼確保不會有重複項，請使用另一個屬性作爲primaryKey或在LastName對象中完全不使用primaryKey。