美文网首页iOS-swiftswift 文章收集
Xcode8,Swift3,CoreData的使用

Xcode8,Swift3,CoreData的使用

作者: OSong | 来源:发表于2016-10-25 21:33 被阅读727次
    <WeChat: sxn8000 文中如有错误望指出>

    注意要添加头文件

    import coredata

     //获得当前应用的AppDelegate对象
        let delegate = UIApplication.shared.delegate as! AppDelegate
    
        //MARK: 增加
        func insert() {
            //Entity实体
            let entity = NSEntityDescription.insertNewObject(forEntityName: "Student", into: delegate.persistentContainer.viewContext) as! Student
            entity.name = "皮卡丘"
            delegate.saveContext()
            
        }
    
    屏幕快照 2016-10-25 下午9.21.16.png
       func delete() {
    
            let request: NSFetchRequest<Student> = Student.fetchRequest()
            let entity = NSEntityDescription.entity(forEntityName: "Student", in: delegate.persistentContainer.viewContext)
            request.entity = entity
            let arr = try! delegate.persistentContainer.viewContext.fetch(request)
            for stu in arr {
                if stu.name == "zhangsan" {
                    delegate.persistentContainer.viewContext.delete(stu)
                    try! delegate.persistentContainer.viewContext.save()
                    
                }
            }
        }
    
    屏幕快照 2016-10-25 下午9.21.24.png
     func update() {
            let request: NSFetchRequest<Student> = Student.fetchRequest()
            let entity = NSEntityDescription.entity(forEntityName: "Student", in: delegate.persistentContainer.viewContext)
            request.entity = entity
            let arr = try! delegate.persistentContainer.viewContext.fetch(request)
            let data = arr[3]
            data.name = "周杰伦"
            try! delegate.persistentContainer.viewContext.save()
        }
    
    屏幕快照 2016-10-25 下午9.21.50.png
     //MARK: 查找
        func fetch() {
     
            let request:NSFetchRequest<Student> = Student.fetchRequest()
            let entity = NSEntityDescription.entity(forEntityName: "Student", in: delegate.persistentContainer.viewContext)
            request.entity = entity
            let arr  = try! delegate.persistentContainer.viewContext.fetch(request)
            for st in arr {
                print(st.name)
            }
            
        }
    
    屏幕快照 2016-10-25 下午9.22.14.png

    相关文章

      网友评论

        本文标题:Xcode8,Swift3,CoreData的使用

        本文链接:https://www.haomeiwen.com/subject/ymxduttx.html