CRUD - 삭제 - Swift SDK

let realm = try! Realm()
// Find the dog we want to update
let wolfie = realm.objects(Dog.self).where {
    $0.name == "Wolfie"
}.first!
// Delete an entry
try! realm.write {
    // Use removeObject(for:)
    wolfie.favoriteParksByCity.removeObject(for: "New York")
    // Or assign `nil` to delete non-optional values.
    // If the value type were optional (e.g. Map<String, String?>)
    // this would assign `nil` to that entry rather than deleting it.
    wolfie.favoriteParksByCity["New York"] = nil
}
XCTAssertNil(wolfie.favoriteParksByCity["New York"])

let realm = try! Realm()
// Record a dog's name and list of cities he has visited.
let dog = Dog()
dog.name = "Maui"
let dogCitiesVisited = ["New York", "Boston", "Toronto"]
try! realm.write {
    realm.add(dog)
    dog.citiesVisited.insert(objectsIn: dogCitiesVisited)
}
XCTAssertEqual(dog.citiesVisited.count, 3)
// Later... we decide the dog didn't really visit Toronto
// since the plane just stopped there for a layover.
// Remove the element from the set.
try! realm.write {
    dog.citiesVisited.remove("Toronto")
}
XCTAssertEqual(dog.citiesVisited.count, 2)
// Or, in the case where the person entered the data for
// the wrong dog, remove all elements from the set.
try! realm.write {
    dog.citiesVisited.removeAll()
}
XCTAssertEqual(dog.citiesVisited.count, 0)

let realm = try! Realm()
// Wolfie's companion is "Fluffy the Cat", represented by a string.
// Fluffy has gone to visit friends for the summer, so Wolfie has no companion.
let wolfie = realm.objects(Dog.self).where {
    $0.name == "Wolfie"
}.first!
try! realm.write {
    // You cannot set an AnyRealmValue to nil; you must set it to `.none`, instead.
    wolfie.companion = .none
}