iOS核心数据：获取的对象多于保存的对象

我不熟悉核心数据，我正试图用它来拯救用户。但是，当我第一次创建用户时，它会插入用户。这似乎很顺利。它只被调用一次

-(void)insertUser: (User *) user{
    [self userToModel:user];
    NSError *error = nil;
    if(![context save:&error]){
        NSLog(@"Unable to save managed object context");
    }
}

-(UserModel *)userToModel:(User *) user{
    UserModel *usermodel = [NSEntityDescription
                            insertNewObjectForEntityForName:@"UserModel"
                            inManagedObjectContext:context];

    [usermodel setValue:user.username forKey:@"username"];
    [usermodel setValue:user.password forKey:@"password"];
    [usermodel setValue:user.sessionid forKey:@"sessionid"];
    [usermodel setValue:[NSNumber numberWithBool:TRUE] forKey:@"selected"];
    [usermodel setValue:[NSNumber numberWithBool:user.beta] forKey:@"beta"];

    return usermodel;
}

接下来，我获取用户，它返回3个用户：2个完全相似的用户和一个nil模型

-(NSMutableArray *)getUsers{
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"UserModel"
                                              inManagedObjectContext:context];
    NSError *error;
    [fetchRequest setEntity:entity];
    NSArray *usermodels= [context executeFetchRequest:fetchRequest error:&error];
    NSMutableArray *users = [[NSMutableArray alloc] init];
    for(UserModel *userModel in usermodels){
        User *user = [self userModelToUser:userModel];
        [users addObject:user];
    }
    return users;
}

UserModelToUser：

-(User *)userModelToUser:(UserModel *)usermodel{
    User *user = [[User alloc]initWithUsername:usermodel.username
                                      Password:usermodel.password
                                     CSRFToken:usermodel.csrftoken
                                     sessionid:usermodel.sessionid
                                          Beta:[usermodel.beta boolValue]
                                      Selected:[usermodel.selected boolValue]];
    return user;
}

选择用户

-(void)selectUser: (User *)userToSelect OldUser:(User *)oldSelectedUser{
    UserModel *oldSelectedUserModel = [self userToModel:oldSelectedUser];
    UserModel *newSelectedUsermodel = [self userToModel:userToSelect];
    [oldSelectedUserModel setValue:[NSNumber numberWithBool:FALSE] forKey:@"selected"];
    [newSelectedUsermodel setValue:[NSNumber numberWithBool:TRUE] forKey:@"selected"];

    NSError *saveError;
    if (![context save:&saveError]) {
        NSLog(@"Changing users failed %@", saveError);
    }
}

---

我已经尝试重新安装该应用程序，以确保没有旧用户仍然保存或任何东西。有人能帮我吗？

设置一个断点或向userToModel添加一个NSLog-验证它只被调用一次。这个方法是你调用InsertNewObjectForEntityForName的唯一地方吗？我已经这样做了，是的。你在userModelToUser中做什么？我将我的用户对象转换为数据库用户模型你能显示代码吗？如果userToModel只被调用一次，那么问题不在这里显示的代码中