在雄辩的ORM（Laravel PHP）中检索关系数据

Question

I'm creating Laravel app and I'm retrieving data from DB with Eloquent ORM while responding with a JSON response. In this example I'm getting matches with some other relevant data by relationship (player1, matchRule...).

public function test() {
    $match = Match::where("state", 2)
        ->with("player1", "player2", "points", "matchRule")->first();

    return response()->json($match); // CASE A
    return response()->json((object) ["id" => $match->id]); // CASE B
    return response()->json((object) ["rule" => $match->match_rule]); // CASE C
}

In case A, everything's fine and all relevant data are returned. Example:

{
   "id": 7,
   "some_other_match_property": "something",
   ...
   "match_rule": {
      "rule_1": "something",
      "rule_2": "something",
   }

}

In case B, I'm getting just id of match and it also works just fine.

{
   "id": 7
}

I case C, I'm trying to get property match_rule but I'm getting null. Why? As you can see, it is present in the $match object when returning the entire match in case A.

{
    "rule": null
}

Answer 1

At first glance I can see that you load your matchRule relationship like this ( camel case ):

$match = Match::where("state", 2)
    ->with("player1", "player2", "points", "matchRule")->first();
                                            ^^^^^^^^^^

But then you are accessing the relationship like this instead ( snake case ):

return response()->json((object) ["rule" => $match->match_rule]);
                                                    ^^^^^^^^^^^

Those are not equivalent. Try this instead:

return response()->json((object) ["rule" => $match->matchRule]);
                                                    ^^^^^^^^^^