Delete binary core data using a func - swift

Question

I want to delete a specific item in a core data binary data set. I have added all of my code below. I tried to follow what I was doing to save the data which worked but trying to apply it to deleting is not currently working. Do not know how to proceed to solve this. I am getting a runtime error at context delete at the helper class.
BASE CLASS
func deleteImage(imageNo:Int) {
// first check the array bounds
let info = DataBaseHelper.shareInstance.fetchImage()
if info.count > imageNo {
// check if the data is available
if let imageData = info[imageNo].img {
DataBaseHelper.shareInstance.deleteImage(data: imageData)
} else {
// no data
print("data is empty")
}
} else {
// image number is greater than array bounds
print("you are asking out of bounds")
}
}
override func viewDidLoad() {
super.viewDidLoad()
deleteImage(imageNo: 2)}
HELPER CLASS
class DataBaseHelper {
static let shareInstance = DataBaseHelper()
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
func deleteImage(data: Data) {
let imageInstance = Info(context: context)
imageInstance.img = data
do {
try context.delete(data)
print("Image is saved")
} catch {
print(error.localizedDescription)
}
}}
error

Answer 1

What you are doing wrong above is
func deleteImage(data: Data) {
// here you create a new object with context
let imageInstance = Info(context: context)
// assigning data to object img property
imageInstance.img = data
// deleting the unsaved object which cause error
do {
try context.delete(data)
print("Image is saved")
} catch {
// this part will be execute because object is not saved
print(error.localizedDescription)
}
}
So the thing is clear first you should have saved object to delete it otherwise it cause error.
So how to delete a specific object
class DataBaseHelper {
static let shareInstance = DataBaseHelper()
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
// pass the object in parameter it will delete the specific info object from CoreData that you will provide in argument
func deleteInfo(info: Info) {
do {
try context.delete(info)
print("Image is saved")
} catch {
print(error.localizedDescription)
}
}
// if you want to remove image but not the info row/object just assign it nil and save again
func deleteImage(info: Info) {
info.img = nil
do {
try context.save()
print("Image is removed but info still here")
} catch {
print(error.localizedDescription)
}
}
}
this how you delete image
if let info = info[imageNo]{
DataBaseHelper.shareInstance.deleteImage(info: info)
}