swift语言IOS8开发战记21 Core Data2

标签：coredata   data model   swift   ios   数据库   

        新年到了，祝大家大家羊年快乐，喜气洋洋。上一话中我们简单地介绍了一些coredata的基本知识，这一话我们通过编程来实现coredata的使用。这一话中建立的几个变量对照上一话中讲到的coredata中重要的变量，在AppDelegate中，添加如下代码：

lazy var applicationDocumentsDirectory:NSURL = {
        let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
        return urls[urls.count - 1] as NSURL
        }() //官方比较推荐的写法

  lazy var managedObjectModel: NSManagedObjectModel = {
        let modelUrl = NSBundle.mainBundle().URLForResource("Model", withExtension: "momd")
        return NSManagedObjectModel(contentsOfURL: modelUrl!)!
        }()//加载model

lazy var persistenetStoreCoordinator:NSPersistentStoreCoordinator = {
        var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
        let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("data.sqlite")
        var error: NSError? = nil
        var failureString = "Three was an error when creating or loading the application's saved data"
        if coordinator?.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
            coordinator = nil
            let dict = NSMutableDictionary()
            dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's save data"
            dict[NSLocalizedFailureReasonErrorKey] = failureString
            dict[NSUnderlyingErrorKey] = error
            error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
            NSLog("Unsolved error\(error), \(error.userInfo)")
            abort()//有错误直接退出
        }
        return coordinator!//没有错误就返回
        
        }()//持久化

   lazy var managedObjectContext:NSManagedObjectContext = {
        let coordinator = self.persistenetStoreCoordinator
        var managedObjectContext = NSManagedObjectContext()
        managedObjectContext.persistentStoreCoordinator = coordinator
        return managedObjectContext
        
        }()//上下文

    func saveContext(){
        if let moc = self.managedObjectContext {
            var error:NSError? = nil
            if moc.hasChanges && !moc.save(&error){
             NSLog("Unsolved error\(error), \(error.userInfo)")
                abort()
            }
        }
    
    }

一路点下去，后面的操作是自动关联的，生成的文件如下：

swift语言IOS8开发战记21 Core Data2

标签：coredata   data model   swift   ios   数据库   

原文地址：http://blog.csdn.net/cg1991130/article/details/43889235