Realm is saving only my most recently added object - ios

Question

I'm trying to save my array of objects in Realm, but Realm appears to be saving only the last object.
This is my model class:
class ContactEntry: Entry {
dynamic var contactId: Int = 0
dynamic var email: String? = ""
dynamic var phone: String? = ""
dynamic var building: String? = ""
dynamic var room: String? = ""
dynamic var contactDescription: String? = ""
dynamic var worktime: String? = ""
dynamic var address: String? = ""
dynamic var personEntries: PersonEntry?
}
This is the base class:
class Entry: Object {
dynamic var id: Int = 0
override static func primaryKey() -> String? { return "id" }
}
This is code I'm using for saving:
func createOrUpdate(entities: [Entity]) {
let entries = toEntries(entities)
let realm = try! Realm()
try! realm.write {
realm.add(entries, update: true)
}
}
func toEntry(entity: Contact) -> ContactEntry {
let entry = ContactEntry()
entry.contactId = entity.id
entry.email = entity.email
entry.phone = entity.phone
entry.building = entity.building
entry.room = entity.room
entry.contactDescription = entity.description
entry.worktime = entity.worktime
entry.address = entity.address
entry.personEntries = personDAO.toEntry(entity.person)
return entry
}
func toEntry(entity: Person) -> PersonEntry {
let entry = PersonEntry()
entry.personId = entity.id
entry.firstname = entity.firstname
entry.middlename = entity.middlename
entry.lastname = entity.lastname
entry.photo = entity.photo
return entry
}
I think that it may be because I have relationship in my model, but I'm not sure why they'd be a problem.
I'm using them as described in the Realm documentation.