iOS: Delete ALL Core Data Swift

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 following:

let appDel: foodforteethAppDelegate = UIApplication.sharedApplication().delegate as foodforteethAppDelegate
    let context: NSManagedObjectContext = appDel.managedObjectContext

Then I've messed around with various methods to try and delete all the core data content but I can't seem to get it to work. I've used removeAll to delete from a stored array but still can't delete from the core data. I assume I need some type of for loop but unsure how to go about making it from the request.

I have tried applying the basic principle of deleting a single row

func tableView(tableView: UITableView!, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath!) {

    let appDel: foodforteethAppDelegate = UIApplication.sharedApplication().delegate as foodforteethAppDelegate
    let context:NSManagedObjectContext = appDel.managedObjectContext

    if editingStyle == UITableViewCellEditingStyle.Delete {

        if let tv = tblTasks {
            context.deleteObject(myList[indexPath!.row] as NSManagedObject)
            myList.removeAtIndex(indexPath!.row)
            tv.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: UITableViewRowAnimation.Fade)
        }

        var error: NSError? = nil
        if !context.save(&error) {
            abort()
        }

    }

}

However, the issue with this is that when I click a button, I don't have the indexPath value and also I need to loop through all the values which I can't seem to do with context.


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")

You can use destroyPersistentStore starting in iOS 9.0 and Swift 3:

public func clearDatabase() {
    guard let url = persistentContainer.persistentStoreDescriptions.first?.url else { return }
    
    let persistentStoreCoordinator = persistentContainer.persistentStoreCoordinator

     do {
         try persistentStoreCoordinator.destroyPersistentStore(at:url, ofType: NSSQLiteStoreType, options: nil)
         try persistentStoreCoordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: nil)
     } catch {
         print("Attempted to clear persistent store: " + error.localizedDescription)
     }
}

To Delete all data you can use NSBatchDeleteRequest

func deleteAllData(entity: String)
{
    let ReqVar = NSFetchRequest(entityName: entity)
    let DelAllReqVar = NSBatchDeleteRequest(fetchRequest: ReqVar)
    do { try ContxtVar.executeRequest(DelAllReqVar) }
    catch { print(error) }
}

I have got it working using the following method:

@IBAction func btnDelTask_Click(sender: UIButton){

    let appDel: foodforteethAppDelegate = UIApplication.sharedApplication().delegate as foodforteethAppDelegate
    let context: NSManagedObjectContext = appDel.managedObjectContext  
    let request = NSFetchRequest(entityName: "Food")

    myList = context.executeFetchRequest(request, error: nil)


    if let tv = tblTasks {

        var bas: NSManagedObject!

        for bas: AnyObject in myList
        {
           context.deleteObject(bas as NSManagedObject)
        }

        myList.removeAll(keepCapacity: false)

        tv.reloadData()
        context.save(nil)
    }
}

However, I am unsure whether this is the best way to go about doing it. I'm also receiving a 'constant 'bas' inferred to have anyobject' error - so if there are any solutions for that then it would be great

EDIT

Fixed by changing to bas: AnyObject


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)
    }
}