[英]Items are not added to Core Data when saving context
我正在嘗試構建一個 Core Data 應用程序,並且我正在使用一些基於這本書的代碼。
為了簡化代碼,我有這樣的事情:
class City: NSManagedObject {
@NSManaged public private(set) var name: String
@NSManaged public private(set) var population: Int
public static func insert(context: NSManagedObjectContext, name: String, population: Int) -> City {
let city: City = context.insertObject()
city.name = name
city.population = population
return city
}
}
extension NSManagedObjectContext {
public func insertObject<A: NSManagedObject>() -> A {
guard let obj = NSEntityDescription.insertNewObjectForEntityForName("City", inManagedObjectContext: self) as? A else {
fatalError("Wrong object type")
}
return obj
}
public func saveOrRoleback() -> Bool {
do {
try save()
return true
} catch {
rollback()
return false
}
}
public func performChanges(block: () -> ()) {
performBlockAndWait {
block()
print(self.saveOrRoleback())
}
}
}
func addCity() {
self.context.performChanges {
City.insert(self.context, name: self.name.text!, amount: Int(self.population.text!))
}
}
當我添加一個新的城市,並save()
被調用內部saveOrRollback()
上下文的方法,我沒有得到任何錯誤,它會返回true。
但是沒有添加數據。 我試圖檢查 sql 文件並且是空的。
作為 Core Data 的新手,有人可以指出我在哪里尋找問題嗎? 原以為保存的時候會報錯什么的,但是好像一切正常,但是數據庫一直都是空的。
編輯: - 添加了核心數據設置
public func createContext() -> NSManagedObjectContext {
let context = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
context.persistentStoreCoordinator = createStoreCoordinator()
return context
}
private func createStoreCoordinator() -> NSPersistentStoreCoordinator {
let psc = NSPersistentStoreCoordinator(managedObjectModel: model.managedObjectModel)
try! psc.addPersistentStoreWithType(model.storeType.type, configuration: nil, URL: model.storeURL, options: nil)
return psc
}
// Main VC
override func viewDidLoad() {
super.viewDidLoad()
let model = CoreDataModel(modelName: modelName, modelBundle: modelBundle!, storeType: .SQLite(DocumentsDirectoryURL()))
let factory = CoreDataFactory(model: model)
context = factory.createContext()
self.todayViewController = storyboard?.instantiateViewControllerWithIdentifier("TodayViewController") as! TodayViewController
self.todayViewController.context = context
}
編輯 2: - 添加數據后的 sql 調試
-06-18 22:31:15.042 Savings+[1100:39698] CoreData: sql: BEGIN EXCLUSIVE
2016-06-18 22:31:15.043 Savings+[1100:39698] CoreData: sql: SELECT Z_MAX FROM Z_PRIMARYKEY WHERE Z_ENT = ?
2016-06-18 22:31:15.043 Savings+[1100:39698] CoreData: sql: UPDATE Z_PRIMARYKEY SET Z_MAX = ? WHERE Z_ENT = ? AND Z_MAX = ?
2016-06-18 22:31:15.043 Savings+[1100:39698] CoreData: sql: COMMIT
2016-06-18 22:31:15.045 Savings+[1100:39698] CoreData: sql: BEGIN EXCLUSIVE
2016-06-18 22:31:15.045 Savings+[1100:39698] CoreData: sql: INSERT INTO ZTRANSACTION(Z_PK, Z_ENT, Z_OPT, ZAMOUNT, ZDATE, ZNAME, ZTYPE) VALUES(?, ?, ?, ?, ?, ?, ?)
2016-06-18 22:31:15.045 Savings+[1100:39698] CoreData: sql: COMMIT
2016-06-18 22:31:15.046 Savings+[1100:39698] CoreData: sql: pragma page_count
2016-06-18 22:31:15.046 Savings+[1100:39698] CoreData: annotation: sql execution time: 0.0003s
2016-06-18 22:31:15.046 Savings+[1100:39698] CoreData: sql: pragma freelist_count
正如評論/聊天中所討論的:
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.