Edit a Single Core Data Entry Rather than All Entries with the Same Attributes

Question

I have a partially working app but am in need of some assistance to get this over the edge. I am trying to edit a single core data object, rather than all objects with the same attribute. This will make sense shortly.

I have a table view controller which has a plus button in the navigation bar; the user clicks it and is presented with a Modal View with 4 text fields: name, event, date and amount. The user adds in this information, presses save and it gets saved to the Core Data database.

I have the following model: Transaction Occasion (title attribute) Item (amountType attribute) Date (dateOEvent attribute) Person (name attribute)

Transaction has a relationship to Occasion, Item, Date and Person.

The app is working very well now when I save new entries; there are no duplicates and it's working well. The tableview controller is set to display the Transactions in the cells and sections with NSFetchedResultsController, so by using the relationships, I can for example set the cell.textLabel.text = transaction.whoBy.name.

When it comes to editing the transactions, here is where there is a slight but serious issue. I click on a cell in the table view and through prepareForSegue, it successfully passes me to a new view controller with the text fields already populated with the information from the cell I clicked on. The problem comes with editing.

If my Table view has 3 entries for Jack and 1 entry for Mary with all the information filled in, like the event title, the date of the event, the amount, etc. That works because in 3 separate cells in the Table view, I see Jack, but with different events, amounts and dates for each of "Jack's" transactions. So:

Cell 1 (name - event - date - amount): Jack - BBQ - Today - 400

Cell 2: Jack - Kid - July - 500

Cell 3: Jack - New House - July - 1000

Cell 4: Mary - Holiday - October - 400

What I want is to click on Cell 1 and change JACK to JOHN. The problem I have now is, with the code you'll see below, if I change Jack to John, cell 1, 2 AND 3 also get changed to John and that is clearly not what I want.

My Detail View Controller for the editing has a Transaction *transaction property so it can set the information passed over from the Table view, and in the viewDidLoad, I have the following, where self.oldName is just a NSString property:

- (void)viewDidLoad
{
    self.editingNameTextField.text = self.selectedTransaction.whoBy.name;
    self.oldName = self.editingNameTextField.text;
    [super viewDidLoad];
}

The Edit Entry Save Method is like this:

- (IBAction)save:(id)sender
{
    NSManagedObjectContext *context = [self managedObjectContext];

    self.selectedTransaction.whoBy.name = self.oldName;
    Person *person = [Person personWithName:self.oldName inManagedObjectContext:context];
    self.selectedTransaction.whoBy = person;
    self.selectedTransaction.whoBy.name = self.editingNameTextField.text;

    // Same code for Occasion, removed for brevity

    NSError *error = nil;
    if (![context save:&error])
    {
        NSLog(@"Can't save! %@ %@", error, [error localizedDescription]);
    }
}

That calls the method personWithName:

+ (Person *)personWithName:(NSString *)name inManagedObjectContext:(NSManagedObjectContext *)context
{
    Person *person = nil;

    // Creating a fetch request to check whether the name of the person already exists
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
    request.predicate = [NSPredicate predicateWithFormat:@"name = %@", name];
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];
    request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor];

    NSError *error = nil;
    NSArray *people = [context executeFetchRequest:request error:&error];
    if (!people)
    {
        // Handle Error
    }
    else if (![people count])
    {
        // If the person count is 0 then let's create it
        person = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:context];
        person.name = name;
    }
    else
    {
        // If the object exists, just return the last object .
        person = [people lastObject];
    }
    return person; 
}

I have to do the same for the Occasion and Date, but my question is starting with the Person, how do I edit a SINGLE transaction in the Table View (the selected Transaction) rather than renaming EVERY name. I just want to edit Cell 1's name text field from Jack to John and have the other cells still remain showing Jack, etc.

Any help would once again be massively appreciated!