public SuperheroQuery(IEntityAdapter <Power> powerAdapter)
{
Field <ListGraphType <PowerType> >(
"powers",
resolve: context => powerAdapter.ReadAll()
);
}
public IEnumerable <Hero> ReadAll()
{
var heroes = new List <Hero>();
using (var connection = new SqlConnection(ConnectionString))
{
var heroQueryString = "SELECT Id, Name, Location FROM Heroes";
var heroCommand = new SqlCommand(heroQueryString, connection);
connection.Open();
using (var reader = heroCommand.ExecuteReader())
{
while (reader.Read())
{
heroes.Add(new Hero((Guid)reader["Id"], (string)reader["Name"], (string)reader["Location"], new List <Power>()));
}
}
// TODO n + 1 query problem, kind of; is there a way to avoid this?
// actually, O(|Heroes| * |Powers|)
foreach (var hero in heroes)
{
var allPowers = PowerAdapter.ReadAll();
foreach (var power in allPowers)
{
var associationQueryString = "SELECT * FROM HeroesPowersAssociation WHERE HeroId = @heroid AND PowerId = @powerid";
var associationCommand = new SqlCommand(associationQueryString, connection);
associationCommand.Parameters.AddWithValue("@heroid", hero.Id);
associationCommand.Parameters.AddWithValue("@powerid", power.Id);
using (var reader = associationCommand.ExecuteReader())
{
if (reader.Read())
{
hero.Powers.Append(power);
}
}
}
}
}
return(heroes);
}