Delete all data from an attribute in CoreData - ios

Question

How to delete all data for example from an attribute <name>, not Entity, from attribute. I have an entity name - Users, attribute - name and I don't know how to delete all data from an attribute.

Answer 1

for delete the all data you can use this function
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)
print("Deleted")
}
} catch let error as NSError {
print(error)
}
}
and after that call the function like this
deleteAllData(entity: "your Entity name")

Answer 2

You have to set that attibute to nil and save the context. This is how you have to remove the attribute from entity. You can't delete it like how an entity is deleted from coreData.

Answer 3

I just renewed Rahuld and Piet.t code for Swift and it works.
func deleteAllData(entity: String) {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedObjectContext = appDelegate.persistentContainer.viewContext
let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: entity)
fetchRequest.returnsObjectsAsFaults = false
do
{
let results = try managedObjectContext.fetch(fetchRequest)
for managedObject in results
{
let managedObjectData:NSManagedObject = managedObject
managedObjectContext.delete(managedObjectData)
print("Deleted")
}
} catch let error as NSError {
print(error)
}
try? managedObjectContext.save()
self.fetch(entity: "ListItem")
}
and after that call the function like this
deleteAllData(entity: "your Entity name")
in addition after you need to show the result so you will fetch your data again.
the below function can be used for it
func fetch(entity: String) {
//Veritabanındaki bilginin ekrana gelmesi için veriyi çekme işlemi
let appDelegate = UIApplication.shared.delegate as? AppDelegate
let managedObjectContext = appDelegate?.persistentContainer.viewContext
let fetchRequest = NSFetchRequest<NSManagedObject>.init(entityName: entity)
data = try! managedObjectContext!.fetch(fetchRequest)
tableView.reloadData()
}
use it like:
self.fetch(entity: "your entity name")
or like this:
fetch(entity: "your entity name")