一.向数据库中存储数据

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1.顶部头文件导入CoreData

2.自定义存储函数

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二.获取数据库数据（应用NSFetchResultController）

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1.顶部头文件导入CoreData

2.定义NSFetchResultController控制器的局部变量:

    var fetchResultController: NSFetchResultController<"此处填写实例对象的名称">!

3.初始化NSFetchResultController

    func initFetchResultController() { 

             let appDelegate = UIApplication.shared.delegate as! AppDelegate

             let context = appDelegate.persistentContainer.viewContext 

             // data内的排序方式 

             let fetchRequest = NSFetchRequest(entityName: "Area") 

             let sd = NSSortDescriptor(key: "name", ascending: true)                       

             fetchRequest.sortDescriptors = [sd] fetchResultController =  

                      NSFetchedResultsController(fetchRequest: fetchRequest,                 

                      managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil) 

              fetchResultController.delegate = self 

               do {

                       try fetchResultController.performFetch() 

                       if let objects =  fetchResultController.fetchedObjects { 

                                     areas = objects

                         } 

                 } catch {

                         print("无法取到数据库\(error)") 

                 }

            }

3.设置界面自动根据响应改变

    func controllerWillChangeContent(_ controller: NSFetchedResultsController) {         

        tableView.beginUpdates()

     } 

     func controllerDidChangeContent(_ controller: NSFetchedResultsController) {

        tableView.endUpdates()

    }

    func controller(_ controller: NSFetchedResultsController, didChange anObject: Any, at         

            indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath:     

            IndexPath?) {

        switch type {

            case .insert:

                tableView.insertRows(at: [newIndexPath!], with: .automatic)

            case .delete:

                tableView.deleteRows(at: [indexPath!], with: .automatic)

            case .update:

                tableView.reloadRows(at: [indexPath!], with: .automatic)

            default:

                tableView.reloadData()

            }

            do {

                try fetchResultController.performFetch()

                if let objects = fetchResultController.fetchedObjects {

                    areas = objects

                }

               } catch  {

                    print("错误为：\(error)")

                }    

    }