Update core data object swift 3 - ios

Question

I want to update a core data object in swift 3. After some googled I didn't found anything about swift 3.
So my question is: how can I update a core data object in swift 3?

Answer 1

Fetch the existing values using a fetch request with a predicate. Use a unique value in the predicate. Once you've fetched the object, update the object with new values and save the context.
let empId = "001"
let fetchRequest:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest.init(entityName: "EmpDetails")
let predicate = NSPredicate(format: "empId = '\(empId)'")
fetchRequest.predicate = predicate
do {
let result = try persistentContainer.viewContext.fetch(fetchRequest)
if let objectToUpdate = result.first as? NSManagedObject {
objectToUpdate.setValue("newName", forKey: "name")
objectToUpdate.setValue("newDepartment", forKey: "department")
objectToUpdate.setValue("001", forKey: "empID")
try persistentContainer.viewContext.save()
}
} catch {
print(error)
}
Using NSManagedObject subclass
let empId = "001"
let fetchRequest: NSFetchRequest<Employee> = Employee.fetchRequest()
fetchRequest.predicate = NSPredicate(format: "%K = %#", #keyPath(Employee.id), empId)
do {
let results = try persistentContainer.viewContext.fetch(fetchRequest)
if let employee = results.first {
employee.name = "new name"
employee.department = "new department"
}
try persistentContainer.viewContext.save()
} catch let error as NSError {
print(error.localizedDescription)
}
Batch updates
Batch updates help to update multiple Core Data objects without having
to fetch anything into memory.
let batchUpdate = NSBatchUpdateRequest(entityName: "Employee")
batchUpdate.propertiesToUpdate = [#keyPath(Employee.isActive): true]
batchUpdate.affectedStores = persistentContainer.viewContext.persistentStoreCoordinator?.persistentStores
batchUpdate.resultType = .updatedObjectsCountResultType
do {
let batchResult = try coreDataStack.managedContext.execute(batchUpdate) as? NSBatchUpdateResult
print(batchResult?.result)
} catch let error as NSError {
print(error.localizedDescription)
}

Answer 2

Pass unique id in variable "id"(Unique variable created in Core data model) and all the variable as you want to update values:
func context() -> NSManagedObjectContext {
let context=(UIApplication.shared.delegate as!AppDelegate).persistentContainer.viewContext
return context
}
func save() {
(UIApplication.shared.delegate as! AppDelegate).saveContext()
}
func UpdateCartByTestId(id:Int64,name:String) {
let fetchRequest =
NSFetchRequest<NSManagedObject>(entityName: "Update")
fetchRequest.returnsObjectsAsFaults = false
fetchRequest.predicate = NSPredicate(format:"id == %d",id)
let result = try? context().fetch(fetchRequest)
if result?.count == 1 {
let dic = result![0]
dic.setValue(id, forKey: "id")
dic.setValue(name, forKey: "name")
save()
}
}