public List <int> AddArtistsToUser(User user, List <string> artistsNames) { List <MySqlCommand> commands = new List <MySqlCommand>(); List <Artist> artists = new List <Artist>(); List <int> artistsId = new List <int>(); foreach (string artistName in artistsNames) { Artist artist = EntitiesFactory.GetArtistFromArtistName(artistName, conn); if (artist != null) { artists.Add(artist); } } foreach (Artist artist in artists) { commands.Add(GetAddArtistCommand(user.Id, artist.Id)); artistsId.Add(int.Parse(artist.Id)); } conn.ExecuteUpdateCommands(commands); return(artistsId); }