在哪裏放置persistentStoreDescriptions？在Swift3 Coredata樣板堆棧

Question

我遷移我的Coredata到新的版本，我把loadPersistentStores和應用之前persistentStoreDescriptions 不會崩潰，但不堅持與它正在這裏移民工作以及事先考慮數據是我的代碼：

lazy var persistentContainer: NSPersistentContainer = { 
    /* 
    The persistent container for the application. This implementation 
    creates and returns a container, having loaded 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. 
    */ 

    let container = NSPersistentContainer(name: "CoreTest3") 

    let description = NSPersistentStoreDescription() 

    description.shouldInferMappingModelAutomatically = true 
    description.shouldMigrateStoreAutomatically = true 

    container.persistentStoreDescriptions = [description] 


    container.loadPersistentStores(completionHandler: { (storeDescription, error) in 
     if let error = error as NSError? { 
      // Replace this implementation with code to handle the error appropriately. 
      // fatalError() 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. 

      /* 
      Typical reasons for an error here include: 
      * The parent directory does not exist, cannot be created, or disallows writing. 
      * The persistent store is not accessible, due to permissions or data protection when the device is locked. 
      * The device is out of space. 
      * The store could not be migrated to the current model version. 
      Check the error message to determine what the actual problem was. 
      */ 
      fatalError("Unresolved error \(error), \(error.userInfo)") 
     } 
    }) 


    return container 
}() 

Answer 1

根據文檔，你必須初始化持久性存儲說明時指定託管對象模型的URL：

let description = NSPersistentStoreDescription(url: storeURL) 

要獲取URL，請個Bundle.URL(forResource:withExtension)