ios – SwiftData:How to handle many-to-many relationship?

I’m developing a social networking app and encountering a persistence issue with friend relationships. Through debugging, I discovered that each user can only be a friend to one other user, meaning two users cannot share a mutual friend. I’m unsure how to handle this many-to-many relationship in SwiftData and would greatly appreciate any assistance. Thank you in advance. Here is my relative code:

@Model
class User: Identifiable {
    @Relationship var Friend: Array<User>
}

if !userInfo[index].Friend.contains(userInfo[indexpre]) {
                            userInfo[index].Friend.append(userInfo[indexpre])
                            userInfo[indexpre].Friend.append(userInfo[index])
                            do {
                                try context.save()
                            print("成功保存")
                            } catch {
                                // 处理保存失败的情况
                                print("保存消息时出错: \(error)")
                            }
                        }