Loading a list of Classes from a Class query

[maxresdefault]

Hi there,

So with our database structure we have relationships between classes, and objects storing multiples of other classes.

For example, a 'Region' class might have a list of 'Enemies' that spawn in it (1-* relationship).

As of testing the system out we can get all of the regions and then get all of the enemies in a separate query with:

SELECT e.id, e.data, e.ether_stuff
FROM enemy e
JOIN region_enemy_link l ON e.id = l.enemy_id
JOIN region r ON r.id = l.region_id
WHERE r.id = 1
However this is two calls to the query and it would be much nicer if the list of enemies could be serialized from the DB in the Region query.

I've tried doing a big SELECT statement and supplying all of the values it would need but the DBManager tells me it can't read the class type.

This is understandable if it can't do it, but I just wanted to check.

Thanks

[echo17]

I'm not sure what your specific requirement is, but you could set up an ORM class like:


public class RegionEnemies
{
// enemy fields
public int e_id { get; set; }
public string e_data { get; set; }
public string e_ether_stuff { get; set; }

// region fields
public int r_id { get; set; }
public string r_name { get; set; } // or whatever fields you have in region
}


and then set up a query like:


SELECT e.id e_id, e.data e_data, e.ether_stuff e_ether_stuff, r.id r_id, r.name r_name
FROM enemy e
JOIN region_enemy_link l ON e.id = l.enemy_id
JOIN region r ON r.id = l.region_id
WHERE r.id = 1


[maxresdefault]

Thanks for the quick reply!

We don't want to retrieve the enemy fields (like name), we want to retrieve the enemy object.

This can be done with multiple queries (i.e. retrieving the regions and then the nested enemies) but it seems like de-serializing two classes with one query is not something that can be done?

Thanks