iOS: Delete ALL Core Data Swift

Question

I am a little confused as to how to delete all core data in swift. I have created a button with an IBAction linked. On the click of the button I have the follow

Answer 1

In Swift 3.0

 func deleteAllRecords() {
        //delete all data
        let context = appDelegate.persistentContainer.viewContext

        let deleteFetch = NSFetchRequest<NSFetchRequestResult>(entityName: "YourClassName")
        let deleteRequest = NSBatchDeleteRequest(fetchRequest: deleteFetch)

        do {
            try context.execute(deleteRequest)
            try context.save()
        } catch {
            print ("There was an error")
        }
    }

Answer 2

For Swift 3.0

func DeleteAllData(){


    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let managedContext = appDelegate.persistentContainer.viewContext
    let DelAllReqVar = NSBatchDeleteRequest(fetchRequest: NSFetchRequest<NSFetchRequestResult>(entityName: "Entity"))
    do {
        try managedContext.execute(DelAllReqVar)
    }
    catch {
        print(error)
    }
}

Answer 3

Similar to above but with AppDelegte call taken out and UIView variable used

var context: NSManagedObjectContext?
//deleting Message

func deleteMessages(entity: String) {
   do {
      let request = NSFetchRequest(entityName: entity)
      print(request)

      if let result = try context!.executeFetchRequest(request) as? [your class of NSManagedObject] {
          for message in result {
             context!.deleteObject(message)
             try context!.save()
             print(message)
             self.tableView.reloadData()
          }
      }
   } catch {
         print("miss")
   }
}

To use call function

self.deleteMessages("TimeMaster")

Answer 4

Swift 4

From iOS 9, there is the possibility of erasing persistent storage. For better maintenance – create NSPersistentStoreCoordinator extension with abstract function.

extension NSPersistentStoreCoordinator {
    func destroyPersistentStore(type: String) -> NSPersistentStore? {
        guard 
            let store = persistentStores.first(where: { $0.type == type }),
            let storeURL = store.url 
        else {
            return nil
        }

        try? destroyPersistentStore(at: storeURL, ofType: store.type, options: nil)

        return store
    }
}

Then destroying SQLite persistent storage looks pretty simple:

let coordinator = persistentContainer.persistentStoreCoordinator
let store = coordinator.destroyPersistentStore(type: NSSQLiteStoreType)

---

Recommendations

1. Update destroyPersistentStore function which is no-nullable and throws specific errors, for example CoreDataError enum.
2. Probably you want to refresh your persistent storage. For this, you can use addPersistentStore function of NSPersistentStoreCoordinator, with retrieved NSPersistentStore object from destroyPersistentStore.

Answer 5

Try this simple solution:

func deleteAllData(entity: String)
{
    let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext
    let fetchRequest = NSFetchRequest(entityName: entity)
    fetchRequest.returnsObjectsAsFaults = false

    do 
    {
        let results = try managedContext.executeFetchRequest(fetchRequest)
        for managedObject in results
        {
            let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
            managedContext.deleteObject(managedObjectData)
        }
    } catch let error as NSError {
        print("Detele all data in \(entity) error : \(error) \(error.userInfo)")
    }
}

Swift 4

func deleteAllData(_ entity:String) {
    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: entity)
    fetchRequest.returnsObjectsAsFaults = false
    do {
        let results = try dataController.viewContext.fetch(fetchRequest)
        for object in results {
            guard let objectData = object as? NSManagedObject else {continue}
            dataController.viewContext.delete(objectData)
        }
    } catch let error {
        print("Detele all data in \(entity) error :", error)
    }
}

Implementation:

 self.deleteAllData("your_entityName")

Answer 6

I use this one for delete all the core data entities in Swift3

func deleteAllCD(){
    for entityName in ["EntityName", "AnotherEntityName"]{
        let request = NSFetchRequest<NSFetchRequestResult>(entityName: entityName)
        let delAllReqVar = NSBatchDeleteRequest(fetchRequest: request)
        do { try persistentContainer.viewContext.execute(delAllReqVar) }
        catch { print(error) }
    }
}