Core Data - Relationship - core-data

Question

Please let me know how to save objects through relationship.
If I have two entities like Notes , Category entity
Note is one to one for Category.
Category Many to one for Notes.
How to save , if we have Category context to Notes..
Please provide me some inputs.
How to save through sets. It would be greatful
I have Employee and Department entities. Department has one to many relationship with Employee. Employee has one to one relationship with Department. I want save object of employee entity using department entity.
Each time I have create new Object for Employee –
import UIKit
import CoreData
class ViewController: UIViewController {
var container: NSPersistentContainer? = (UIApplication.shared.delegate as? AppDelegate)?.persistentContainer
let appDelegate = UIApplication.shared.delegate as! AppDelegate
var empSet = NSSet()
var empS = Set<EmployeeExample>()
override func viewDidLoad() {
super.viewDidLoad()
var context:NSManagedObjectContext = (container?.viewContext)!
let dept = NSEntityDescription.insertNewObject(forEntityName: "Department", into: context) as! Department
let emp = NSEntityDescription.insertNewObject(forEntityName: "Employee", into: (container?.viewContext)!) as! Employee
emp.firstName = "YYYY"
emp.lastName = "HHHHHHH"
empS.insert(emp)
print("Count of Emp SSSS Set == \(empS.count)")
let emp1 = NSEntityDescription.insertNewObject(forEntityName: "Employee", into: (container?.viewContext)!) as! Employee
emp1.firstName = "RRRRR"
emp1.lastName = "YYYYY"
empS.insert(emp1)
empSet.addingObjects(from: empS)
dept.deptName = "CCC"
print("Count of Emp SSSS Set == \(empS.count)")
print("Count of Emp Set == \(empSet.count)")
dept.addToEmp(empSet)
do {
try appDelegate.saveContext()
print("Saved -------------")
}catch {
print("Error")
}
}
}

Answer 1

I have doubt in these lines anEmployee.department = newDepartment How to get the newDepartment value. Whether i have to declare let newDepartment = NSEntityDescription.insertNewObject(forEntityName: "Department", into: (container?.viewContext)!) as! Department.
The Department object here is whatever object should be related to that specific Employee object. How you get it depends on how your app works, but you probably want to do one of these:
If the employee belongs to a new department that doesn't already exist in your app, you create a new instance of Department and assign that object as anEmployee.department.
If the employee belongs to a department that already exists in your app, you use an already existing Department. You probably get that by fetching Department objects from Core Data-- either with NSFetchRequest or by using an NSFetchedResultsController.