What overhead ormLite has when querying or creating object with ForeignCollection?

Question

I have a table with Players and an other table with Games. There is Player----(1..n)[Game] relationship between them (field definitions may not be entirely correct):

// Player
@DatabaseField(generatedId = true)
private int id;
@DatabaseField
public String name;

@ForeignCollectionField(
    eager = true,
    maxEagerLevel = 3)
public ForeignCollection<Game> games;


// Game
@DatabaseField
String title;

@DatabaseField
String playerName;

I would like to get and return a list of all games. When is the overhead letting ormLite do the select for the ForeignCollection? Or would it be better to do something like this:

    final List<Game> allGames = daoGames.getAllGroupedByName();
    final List<Player> allPlayers = gameDao.getAll();

    final HashMap<String, List<Game>> games = new HashMap<String, List<Game>>();
    for (Game currentGame : allGames) {
        final String player = currentGame.playerName;
        if (games.get(player) == null) {
            games.put(player, new ArrayList<Game>());
        }
        final List<Game> gamesOfPlayer = games.get(player);
        gamesOfPlayer.add(currentGame);
    }
    for (Player player : allPlayers) {
        player.games = games.get(player.name);
    }

My guess is ormLite would do a query for each and every player. Is it a big overhead compared to the one daoGames.getAllGroupedByName() (though the groupBy is not even needed)?

Answer 1

My guess is ormLite would do a query for each and every player. Is it a big overhead compared to the one daoGames.getAllGroupedByName() (though the groupBy is not even needed)?

This is correct. ORMLite does not do this very efficiently with a separate query for each Player result. Your mechanism to do the getAll() and match them up by hand would most likely be faster.

I'd use an ArrayList unless you really need LinkedList capabilities.