Question

I have spent hours looking how to solve this. When I try to get parent from a child all but it’s id fields are empty. It just makes no sense. I am using PlayFramework 2.0.4 if that might indicate anything (besides a terrible choice of framework).

TRoute.java (parent)

@Entity  
@Table(name="routes")
public class TRoute extends Model {

    @Id
    public String route_id;
    public String agency_id;
    @Constraints.Required
    public String route_short_name;
    @Constraints.Required
    public String route_long_name;
    public String route_desc;
    @Constraints.Required
    public String route_type;
    public String route_url;
    public String route_color;
    public String route_text_color;

    @OneToMany(mappedBy="troute")
    public List<Trip> trips;

    public static Finder<String, TRoute> find = new Finder(
            String.class, TRoute.class
    );

}

Trip.java (child)

@Entity  
@Table(name="trips")
public class Trip extends Model {

    @Constraints.Required
    public String route_id;
    @Constraints.Required
    public String service_id;
    @Id
    public String trip_id;
    public String trip_headsign;
    public String direction_id;
    public String block_id;
    public String shape_id;

    @ManyToOne
    @JoinColumn(name="route_id")
    public TRoute troute;

    public static List<Trip> byRouteId(String route_id) {
        List<Trip> trips = 
            Trip.find
            .where().like("route_id", route_id)
            .findList();
        return trips;
    }

    public static Finder<String, Trip> find = new Finder(
            String.class, Trip.class
    );

}

Answer 1

The finder has a fetch() method which can be used to load properties of the other table. Something like:

public static List<Trip> byRouteId(String route_id) {
    List<Trip> trips = List<Trip> trips = Trip.find
        .fetch("troute") // fetch the other table's properties here
        .where()
        .like("route_id", route_id)
        .findList();
    return trips;
}