image.png

//项目创建成功后，在项目文件夹中将自动生成一个拥
有.xcdatamodelId扩展名的文件，该文件可以使用图形化的方式编辑数据
模型，在该文件中包含了Entities、Properties、Attributes、Relationships 4
个概念，和关系型数据库有很大的相似性

image.png

//首先点击底部的【Add Entity】按钮，添加一个新的实体，接着将
实体的名称修改为User。然后在【Attributes】设置区，点击+加号图标
为User实体添加一个新的属性userName，并设置Type类型为String。最
后使用相同的方式，为User实体添加第二个属性password。
//完成Entity模型的创建之后，接着来创建一个托管对象类
NSManagedObject。在项目名称文件夹上点击鼠标右键，然后选择菜单
中的【New File……】命令。在弹出的文件模板选择窗口中，依次选择
【Core Data>NSManagedObject subclass】选项，创建一个
NSManagedObject的子类

image.png

image.png

1 import UIKit
2 import CoreData
3
4 class ViewController：UIViewController {
5 override func viewDidLoad() {
6 super.viewDidLoad()
7 // Do any additional setup after loading the view,
typically from a nib.
8
9 let appDelegate：AppDelegate =
UIApplication.shared().delegate as！AppDelegate
10 let managedObjectContext =
appDelegate.managedObjectContext
11
12 let newUser =
NSEntityDescription.insertNewObject(forEntityName：“User”,
into： managedObjectContext) as！User
13
14 newUser.userName = “John”
15 newUser.password = “123456”
16
17 do{
18 try managedObjectContext.save()
19 print(“成功保存数据。”)
20 }catch
21 {
22 print(“保存数据失败。”)
23 }
24 }
25 }

//2
1 import UIKit
2 import CoreData
3
4 class ViewController：UIViewController {
5
6 override func viewDidLoad() {
7 super.viewDidLoad()
8 // Do any additional setup after loading the view,
typically from a nib.
9
10 let appDelegate：AppDelegate =
UIApplication.shared.delegate as！AppDelegate
11 let managedObjectContext =
appDelegate.managedObjectContext
12
13 let entity：NSEntityDescription？=
NSEntityDescription.entity(forEntityName：“User”,
14 in：managedObjectContext)
15 let request = NSFetchRequest<User>
(entityName：“User”)
16 request.fetchOffset = 0
17 request.fetchLimit = 10
18 request.entity = entity
19
20 let predicate = NSPredicate(format：“userName=
‘John’ “, ””)
21 request.predicate = predicate
22
23 do{
24 let results：[AnyObject]？= try
managedObjectContext.fetch(request)
25
26 for user：User in results as！[User]{
27 print(“userName=(user.userName！)”)
28 print(“password=(user.password！)”)
29 }
30 }
31 catch{
32 print(“获取数据失败。”)
33 }
34 }
35 }

//修改
1 import UIKit
2 import CoreData
3
4 class ViewController：UIViewController {
5 override func viewDidLoad() {
6 super.viewDidLoad()
7 // Do any additional setup after loading the view,
typically from a nib.
8 let appDelegate：AppDelegate =
UIApplication.shared.delegate as！AppDelegate
9 let managedObjectContext =
appDelegate.managedObjectContext
10
11 let entity：NSEntityDescription？=
NSEntityDescription.entity(forEntityName：“User”,
12 in：managedObjectContext)
13 let request = NSFetchRequest<User>
(entityName：“User”)
14 request.fetchOffset = 0
15 request.fetchLimit = 10
16 request.entity = entity
17
18 let predicate = NSPredicate(format：“userName=
‘Jerry’ “, ””)
19 request.predicate = predicate
20
21 do{
22 let results：[AnyObject]？= try
managedObjectContext.fetch(request)
23 for user：User in results as！[User]{
24 user.userName = “Peter”
25 }
26 try managedObjectContext.save()
27
28 request.predicate = nil
29 let newResults：[AnyObject]？= try
managedObjectContext.fetch(request)
30
31 for user：User in newResults as！[User]{
32 print(“userName：(user.userName)”)
33 print(“password：(user.password)”)
34 }
35 }
36 catch{
37 print(“获取数据失败。”)
38 }
39 }
40 }

//删除
23 for user：User in results as！[User]{
24 managedObjectContext.delete(user)
25 }