Delete Data from Coredata Swift

Delete Data from Coredata Swift

Update on my coding issue with executing a delete of data in swift and coredata. This the code I ended up with that worked.

override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
        switch editingStyle {
        case .Delete:
            // remove the deleted item from the model
            let appDel:AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
            let context:NSManagedObjectContext = appDel.managedObjectContext!
            context.deleteObject(myData[indexPath.row] as NSManagedObject)
            myData.removeAtIndex(indexPath.row)
            context.save(nil)

           //tableView.reloadData()
            // remove the deleted item from the `UITableView`
            self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        default:
            return

        }
}

EDIT Above for Swift 2.2 and Xcode 7.3.1

override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
    switch editingStyle {
    case .Delete:
        // remove the deleted item from the model
        let appDel:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        let context:NSManagedObjectContext = appDel.managedObjectContext
        context.deleteObject(myData[indexPath.row] )
        myData.removeAtIndex(indexPath.row)
        do {
            try context.save()
        } catch _ {
        }

        // remove the deleted item from the `UITableView`
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    default:
        return
    }
}

Also need was these two lines of code to be corrected.

    var myData: Array<AnyObject> = []
let managedObjectContext = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext

how to delete particular record in coredata using Swift?

Don't use a custom class. Use only the provided User class.

First of all declare a data source array (replacing displayDatasssss)

var users = [User]()

In the tap method load the data and insert new items in the Core Data stack. Consider that each tap on the button inserts duplicate items into the database. Older entries are not removed.

As User has only name and id properties email is assigned to id.

The items are appended to the data source array and saved in the context.

@IBAction func tap(_ sender: Any) {
    let url = "http://jsonplaceholder.typicode.com/users")!
    let task = session.dataTask(with: url){ [unowned self] (data, response,error)in
        if let error = error { print(error); return }
        do {
            // Array of Data
            let fetchData = try JSONSerialization.jsonObject(with: data!) as! [[String:Any]]    
            for eachDataItem in fetchData {                   
                let name = eachdataitem["name"] as! String
                let email = eachdataitem["email"] as! String
                let newUser = User(context: self.context)
                newUser.name = name
                newUser.id = email
                self.users.append(newUser)
            }
            DispatchQueue.main.async {
               self.tableView.reloadData()
            }
            try self.context.save()
       } catch{
           print("Error 2", error)
       }
    }
    task.resume()
}

In viewDidLoad fetch the data from CoreData and reload the table view

override func viewDidLoad() {
    super.viewDidLoad()
    do {
       let request : NSFetchRequest<User> = User.fetchRequest()
       users = try context.fetch(request)
       tableView.reloadData()
    } catch { print(error) }
}

In cellForRow assign the property value(s) to the labels, nothing else

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell1") as! TableViewCell1 
    let user = users[indexPath.row]
    cell.label.text = user.name  
    return cell
}

The delete method is quite similar to yours

let deleteAction = UITableViewRowAction(style: .default, title: "Delete", handler: { [unowned self] (action, indexPath) in
    print("Delete tapped")

    // remove the deleted item from the model
    let objectToDelete = self.users.remove(at: indexPath.row)
    self.context.delete(objectToDelete)
    do {
        try self.context.save()
        self.tableView.deleteRows(at: [indexPath], with: .automatic)
    } catch {
       print(error)
    }
}
return [editAction, deleteAction]

Note: Print always errors, don't ignore them or print only meaningless literal strings

how to delete row from coredata (Entity) ios swift

Try Like this,

func buttonDeletePressed(sender:UIButton) {

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

        let index = sender.tag

        context.deleteObject(people[index] as NSManagedObject)
        people.removeAtIndex(index)

        let _ : NSError! = nil
        do {
            try context.save()
            self.tableView.reloadData()
        } catch {
            print("error : \(error)")
        }
}

Hope this will help you.

Deleting from Core Data Swift 4

In coredata every object should have Id if you want to delete it , like this

let fetchRequest: NSFetchRequest<Favorite> = Favorite.fetchRequest()
fetchRequest.predicate = Predicate.init(format: "FavoriteID==\(ID)")

do {
    let objects = try context.fetch(fetchRequest)
    for object in objects {
        context.delete(object)
    }
    try context.save()
} catch _ {
    // error handling
}

iOS: Delete ALL Core Data Swift

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

Delete data from CoreData

The IndexSet method works when you are using onDelete with a ForEach loop.

Since you don't have access to the IndexSet with a Button you pass the actual item.

Change your function to this.

public func deleteTodo(todoDB: TodoDB){
        managedObjectContext.delete(todoDB)
        do{
            try managedObjectContext.save()
        } catch{
            print(error)
        }
}

And put this code within the trash button's action like this.

deleteTodo(todoDB: todoDB)

Swift 3: How to delete the single record in the Core Data when a UIbutton is Pressed

    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "FavProfile")
    let predicate = NSPredicate(format: "profileID == %@", id as CVarArg)
    fetchRequest.predicate = predicate
    let moc = getContext()
    let result = try? moc.fetch(fetchRequest)
    let resultData = result as! [FavProfile]

    for object in resultData {
        moc.delete(object)
    }

    do {
        try moc.save()
        print("saved!")
    } catch let error as NSError  {
        print("Could not save \(error), \(error.userInfo)")
    }

use predicate for profileID.

Delete a record from an Entity in core data

If you are trying to delete item with specific index, i have provided solution for deleting item at index (this might cause array out of bound exception), but i recommend to use predicate, lets say that may be id, name of item that you are willing to delete.

I am providing solution with perception from your question,
You can use process of fetching entity from DB and delete that particular item you want to remove.

Please manage to add following code, Do not forgot to use predicate if you want to delete some particular item

 func deleteCoreData(rowIndex: Int) {

    let managedContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext

    do{
        //1. Create Request
        let request: NSFetchRequest<PlayListDetails> = PlayListDetails.fetchRequest()

        //Predicate is optional as per need
        //let predicate = NSPredicate(format: "playlistId = %@", id)
        //request.predicate = predicate

        //2. Result object
        let results = try managedObjectcontext.fetch(request as! NSFetchRequest<NSFetchRequestResult>)

        guard results.count > 0 else {
            print("No tems available handle error")
            return
        }

        for i in 0...results.count-1 {

            if i == rowIndex {
                let theItem = results[index] as NSManagedObject
                managedObjectcontext.delete(item)
            }
        }
         /*
        for item in results as! [NSManagedObject]{
            print(item)
            //hit delete for item you want
            managedObjectcontext.delete(item)
        } */

        do {
            try managedObjectcontext.save() // <- remember to put this :)

        } catch {
            // Do something... fatalerror
            print("handle error")
            return
        }

    } catch{
        print(error)
        print("handle error")
        return

    }
    print("handle error")

}

Update

"This is the query i wants to execute sir.. Delete all from PlayListDetails where trackId=123 and playlistName= demo How would I achieve this in above code"

Using predicate

//use predicate for single predicate and compound for multiple predicate 
//Predicate is optional as per need
let predicate = NSPredicate(format: "trackId = %@", id)
let predicate2 = NSPredicate(format: "name = %@", "some name")

//let compoundPredicate = NSCompoundPredicate(andPredicateWithSubpredicates: [predicate, predicate2])

    request.predicate = predicate

on delete section use

for item in results as! [NSManagedObject]{
                print(item)
                //hit delete for item you want
                managedObjectcontext.delete(item)
            } 

---

Related Topics