更新核心数据对象 swift 3

我想更新 swift 3 中的核心数据对象。经过一番谷歌搜索后，我没有找到任何有关 swift 3 的信息。 所以我的问题是：如何更新 swift 3 中的核心数据对象？

使用带有谓词的获取请求来获取现有值。在谓词中使用唯一值。获取对象后，使用新值更新对象并保存上下文。

let empId = "001"
let fetchRequest:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest.init(entityName: "EmpDetails")
let predicate = NSPredicate(format: "empId = '\(empId)'")
fetchRequest.predicate = predicate
do {
    let result = try persistentContainer.viewContext.fetch(fetchRequest)
    if let objectToUpdate = result.first as? NSManagedObject {
        objectToUpdate.setValue("newName", forKey: "name")
        objectToUpdate.setValue("newDepartment", forKey: "department")
        objectToUpdate.setValue("001", forKey: "empID")
        try persistentContainer.viewContext.save()
    }
} catch {
    print(error)
}

使用 NSManagedObject 子类

let empId = "001"
let fetchRequest: NSFetchRequest<Employee> = Employee.fetchRequest()
fetchRequest.predicate = NSPredicate(format: "%K = %@", #keyPath(Employee.id), empId)
do {
  let results = try persistentContainer.viewContext.fetch(fetchRequest)
  if let employee = results.first {
    employee.name = "new name"
    employee.department = "new department"
  }
  try persistentContainer.viewContext.save()
} catch let error as NSError {
  print(error.localizedDescription)
}

批量更新

批量更新有助于更新多个 Core Data 对象，而无需 将任何内容读取到内存中。

let batchUpdate = NSBatchUpdateRequest(entityName: "Employee")
batchUpdate.propertiesToUpdate = [#keyPath(Employee.isActive): true]
batchUpdate.affectedStores = persistentContainer.viewContext.persistentStoreCoordinator?.persistentStores
batchUpdate.resultType = .updatedObjectsCountResultType
do {
  let batchResult =  try coreDataStack.managedContext.execute(batchUpdate) as? NSBatchUpdateResult
  print(batchResult?.result)
} catch let error as NSError {
  print(error.localizedDescription)
}