1
我有EmployeeExample
和Deptt
为实体。CoreData:关系:保存:查询
EmployeeExample
一个与Dept
Dept
一个关系与EmployeeExample
- 我想通过关系,将数据保存多个关系。我有部门的实体对象,与我要救
employeeexample
实体
我实现这一点,但我想知道是否是最佳的方式。任何最佳方式?我想知道这种关系是如何工作的。
我的代码:
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: "Deptt", into: context) as! Deptt
let emp = NSEntityDescription.insertNewObject(forEntityName: "EmployeeExample", into: (container?.viewContext)!) as! EmployeeExample
emp.firstName = "YYYY"
emp.lastName = "HHHHHHH"
empS.insert(emp)
print("Count of Emp SSSS Set == \(empS.count)")
let emp1 = NSEntityDescription.insertNewObject(forEntityName: "EmployeeExample", into: (container?.viewContext)!) as! EmployeeExample
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 {}
}
}
难道我每次都要创建一个Employee
实例?