[swift] CoreData (1) 建立CoreData

CoreData是是一種以物件導向方式讓開發者與跟資料庫互動的框架,好處是你不需要懂SQL也能對SQLite做操作

[![](https://1.bp.blogspot.com/-cLEXYUQDTJA/VQJMODzIHuI/AAAAAAAAEjg/uDb2WQBOTmA/s1600/S__23961604.jpg)](http://1.bp.blogspot.com/-cLEXYUQDTJA/VQJMODzIHuI/AAAAAAAAEjg/uDb2WQBOTmA/s1600/S__23961604.jpg)[ ](http://1.bp.blogspot.com/-cLEXYUQDTJA/VQJMODzIHuI/AAAAAAAAEjg/uDb2WQBOTmA/s1600/S__23961604.jpg)

接著來筆記如何實作CoreData,首先先建立一個專案並把Use Core Data勾選起來

接著打開AppDelegate最下面可以看到多了一大堆程式碼 ```js
// MARK: - Core Data stack

  lazy var applicationDocumentsDirectory: NSURL = {
  // The directory the application uses to store the Core Data store file. This code uses a directory named "tw.com.xxx.Coredata" in the application's documents Application Support directory.
  let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
  return urls[urls.count-1] as NSURL

}()

  lazy var managedObjectModel: NSManagedObjectModel = {
  // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
  let modelURL = NSBundle.mainBundle().URLForResource("Coredata", withExtension: "momd")!
  return NSManagedObjectModel(contentsOfURL: modelURL)!

}()

  lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
  // The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
  // Create the coordinator and store
  var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
  let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("Coredata.sqlite")
  var error: NSError? = nil
  var failureReason = "There was an error creating or loading the application's saved data."
  if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
      coordinator = nil
      // Report any error we got.
      let dict = NSMutableDictionary()
      dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
      dict[NSLocalizedFailureReasonErrorKey] = failureReason
      dict[NSUnderlyingErrorKey] = error
      error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
      // Replace this with code to handle the error appropriately.
      // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
      NSLog("Unresolved error \(error), \(error!.userInfo)")
      abort()
  }
  return coordinator

}()

  lazy var managedObjectContext: NSManagedObjectContext? = {
  // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
  let coordinator = self.persistentStoreCoordinator
  if coordinator == nil {
      return nil
  }
  var managedObjectContext = NSManagedObjectContext()
  managedObjectContext.persistentStoreCoordinator = coordinator
  return managedObjectContext

}()

  // MARK: - Core Data Saving support

  func saveContext () {
  if let moc = self.managedObjectContext {
      var error: NSError? = nil
      if moc.hasChanges && !moc.save(&error) {
          // Replace this implementation with code to handle the error appropriately.
          // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
          NSLog("Unresolved error \(error), \(error!.userInfo)")
          abort()
      }
  }

}


*   接著建立物件託管模型
[![](https://1.bp.blogspot.com/-KK3Tu_Vazbk/VQJTyV8AxfI/AAAAAAAAEj8/YqCpExRBFF0/s400/%E8%9E%A2%E5%B9%95%E5%BF%AB%E7%85%A7%2B2015-03-13%2B%E4%B8%8A%E5%8D%8811.02.54.png)](http://1.bp.blogspot.com/-KK3Tu_Vazbk/VQJTyV8AxfI/AAAAAAAAEj8/YqCpExRBFF0/s1600/%E8%9E%A2%E5%B9%95%E5%BF%AB%E7%85%A7%2B2015-03-13%2B%E4%B8%8A%E5%8D%8811.02.54.png)
*   接著建立Entities
[![](https://1.bp.blogspot.com/-D2JtYHHTBxI/VQJUguKuVhI/AAAAAAAAEkE/2vxmi1ktG4U/s400/%E8%9E%A2%E5%B9%95%E5%BF%AB%E7%85%A7%2B2015-03-13%2B%E4%B8%8A%E5%8D%8811.07.18.png)](http://1.bp.blogspot.com/-D2JtYHHTBxI/VQJUguKuVhI/AAAAAAAAEkE/2vxmi1ktG4U/s1600/%E8%9E%A2%E5%B9%95%E5%BF%AB%E7%85%A7%2B2015-03-13%2B%E4%B8%8A%E5%8D%8811.07.18.png)
＊**<span style="color: blue;">圖片需要用Binary Data來儲存 </span>**
*   接著建立Class來對應Entity ```js
import Foundation
import CoreData
class Friend:NSManagedObject  {
    @NSManaged var name:String!
    @NSManaged var tel:NSNumber!
    @NSManaged var picture:NSData!
    @NSManaged var marry:NSNumber!
}

＊對應Entity中的Boolean, Integer, Float and Double attributes,都是用NSNumber

接著設定Entity與Class的對應關係,如圖：

這樣託管物件的建立就已經完成了,下一篇介紹如何叫用