MySQLのconcatに近いか。
userFetch.predicate = NSPredicate(format: “name = %@”, “John”) で条件一致を求める。
override func viewDidLoad() {
super.viewDidLoad()
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.persistentContainer.viewContext
let userEntity = NSEntityDescription.entity(forEntityName: "User", in: managedContext)!
let user = NSManagedObject(entity: userEntity, insertInto: managedContext)
user.setValue("John", forKeyPath: "name")
user.setValue("john@test.com", forKey: "email")
let formatter = DateFormatter()
formatter.dateFormat = "yyyy/MM/dd"
let date = formatter.date(from: "1990/10/08")
user.setValue(date, forKey: "date_of_birth")
user.setValue(0, forKey: "number_of_children")
let carEntity = NSEntityDescription.entity(forEntityName: "Car", in:managedContext)!
let car1 = NSManagedObject(entity: carEntity, insertInto: managedContext)
car1.setValue("Audi TT", forKey: "model")
car1.setValue(2010, forKey: "year")
car1.setValue(user, forKey: "user")
let car2 = NSManagedObject(entity: carEntity, insertInto: managedContext)
car2.setValue("BMW X6", forKey: "model")
car2.setValue(2014, forKey:"year")
car2.setValue(user, forKey: "user")
do {
try managedContext.save()
} catch {
print("Failed saving")
}
let userFetch = NSFetchRequest<NSFetchRequestResult>(entityName: "User")
userFetch.fetchLimit = 1
userFetch.predicate = NSPredicate(format: "name = %@", "John")
userFetch.sortDescriptors = [NSSortDescriptor.init(key: "email", ascending: true)]
let users = try! managedContext.fetch(userFetch)
let john: User = users.first as! User
print("Email: \(john.email!)")
let johnCars = john.cars?.allObjects as! [Car]
print("has \(johnCars.count)")
}
ちょっと雑だが、次は地図に行ってみよう。