您知道有什么方法可以删除存储在Core Data中的所有条目吗?我的schema应该保持不变;我只想把它重置为空白。
Edit
我希望以编程方式做到这一点,这样用户就可以基本上按下重置按钮。
您知道有什么方法可以删除存储在Core Data中的所有条目吗?我的schema应该保持不变;我只想把它重置为空白。
Edit
我希望以编程方式做到这一点,这样用户就可以基本上按下重置按钮。
当前回答
Swift 4/5, iOS 9+
重新构建整个CoreData SQLite文件将确保擦除所有数据,因此删除所有实体。只需调用deleteAndRebuild()。
class CoreDataStack {
// Change this
static let datamodelName = "ProjectName"
static let storeType = "sqlite"
static let persistentContainer = NSPersistentContainer(name: datamodelName)
private static let url: URL = {
let url = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0].appendingPathComponent("\(datamodelName).\(storeType)")
assert(FileManager.default.fileExists(atPath: url.path))
return url
}()
static func loadStores() {
persistentContainer.loadPersistentStores(completionHandler: { (nsPersistentStoreDescription, error) in
if let error = error {
fatalError(error.localizedDescription)
}
})
}
static func deleteAndRebuild() {
try! persistentContainer.persistentStoreCoordinator.destroyPersistentStore(at: url, ofType: storeType, options: nil)
loadStores()
}
}
其他回答
接受的答案是正确的,通过NSFileManager删除URL是正确的,但正如在iOS 5+编辑中所述,持久存储不仅仅由一个文件表示。对于SQLite存储,它是*。sqlite, *。Sqlite-shm和*。sqlite-wal……幸运的是,自从iOS 7+我们可以使用方法
[NSPersistentStoreCoordinator + removeUbiquitousContentAndPersistentStoreAtURL选项:错误:):
为了处理删除,代码应该是这样的:
NSPersistentStore *store = ...;
NSError *error;
NSURL *storeURL = store.URL;
NSString *storeName = ...;
NSPersistentStoreCoordinator *storeCoordinator = ...;
[storeCoordinator removePersistentStore:store error:&error];
[NSPersistentStoreCoordinator removeUbiquitousContentAndPersistentStoreAtURL:storeURL.path options:@{NSPersistentStoreUbiquitousContentNameKey: storeName} error:&error];
我写了一个clearStores方法,遍历每个存储,并从协调器和文件系统中删除它(错误处理不考虑):
NSArray *stores = [persistentStoreCoordinator persistentStores];
for(NSPersistentStore *store in stores) {
[persistentStoreCoordinator removePersistentStore:store error:nil];
[[NSFileManager defaultManager] removeItemAtPath:store.URL.path error:nil];
}
[persistentStoreCoordinator release], persistentStoreCoordinator = nil;
这个方法在一个coreDataHelper类中,它负责在persistentStore为nil时创建persistentStore。
龙道9+ Swift 2
删除所有实体中的所有对象
func clearCoreDataStore() {
let entities = managedObjectModel.entities
for entity in entities {
let fetchRequest = NSFetchRequest(entityName: entity.name!)
let deleteReqest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
do {
try context.executeRequest(deleteReqest)
} catch {
print(error)
}
}
}
迅速的解决方案:
class func deleteAllManagedObjects() {
let modelURL = NSBundle.mainBundle().URLForResource("some string", withExtension: "mom")
let mom = NSManagedObjectModel(contentsOfURL: modelURL)
for entityName in mom.entitiesByName.keys {
let fr = NSFetchRequest(entityName: entityName as String)
let a = Utility.managedObjectContext().executeFetchRequest(fr, error: nil) as [NSManagedObject]
for mo in a {
Utility.managedObjectContext().deleteObject(mo)
}
}
Utility.managedObjectContext().save(nil)
}
Swift 5.1解决方案
public static func reset() {
let coordinator = _persistentContainer.persistentStoreCoordinator
for store in coordinator.persistentStores where store.url != nil {
try? coordinator.remove(store)
try? FileManager.default.removeItem(atPath: store.url!.path)
}
}