Laravel ManyToMany relation with singular table names - laravel

Question

I want to create ManyToMany relation between samples and supposed_origins.
In my firm, our convention is to have singular table names, so as mentioned in https://laravel.com/docs/8.x/eloquent#table-names, I defined :
migrations
Schema::create('v3_sample', function (Blueprint $table) {
$table->increments('id');
$table->string('number_canonical', 6)->unique(); // business key
$table->string('name')->nullable();
};
Schema::create('v3_supposed_origin', function (Blueprint $table) {
$table->increments('id');
$table->integer('location_id')->unsigned(); // from other database
$table->string('description');
});
Schema::create('v3_sample_supposed_origin', function (Blueprint $table) {
$table->increments('id');
$table->integer('sample_id')->unsigned();
$table->foreign('sample_id')->references('id')->on('v3_sample')->onDelete('cascade');
$table->integer('supposed_origin_id')->unsigned();
$table->foreign('supposed_origin_id')->references('id')->on('v3_supposed_origin')->onDelete('cascade');
});
models
class Sample extends Model
{
protected $table = 'v3_sample';
public function supposed_origins() {
dd($this);
return $this->belongsToMany('App\SupposedOrigin');
}
}
class SupposedOrigin extends Model
{
protected $table = 'v3_supposed_origin';
public function samples() {
return $this->belongsToMany('App\Sample');
}
}
and controller
class SampleController extends Controller
{
// […]
public function edit(Request $request, $number_canonical)
{
$sample_record = DB::table('v3_sample')->where('number_canonical', $number_canonical)->first();
$supposed_origins = $sample_record->supposed_origins;
dd($supposed_origins); // returns ErrorException Undefined property: stdClass::$supposed_origins
and SampleController returns ErrorException Undefined property: stdClass::$supposed_origins
As I have singular table names, the rule that define to have pivot table with singular table names (sample_supposed_origin) to plural table names (samples and supposed_origins instead of my sample an supposed_origin) are not followed !
Questions :
Is singular naming the reason it can't find the relation?
Is there a way to specify it correctly? Add pivot table model?
Additional informations : Laravel Framework 7.28.4, PHP 8.0.3, mariadb Ver 15.1 Distrib 10.1.47-MariaDB

Answer 1

Your issue is that you are using the Query Builder, and not the Eloquent Query Builder.
DB::table('v3_sample')->where('number_canonical', $number_canonical)->first() will return an object representing the results from the database, but it is just a standard PHP Object.
You want:
Sample::query()->where('number_canonical', $number_canonical)->first()
This will return a Sample Model and you will have access to the relation you need.
In your case $sample_record->supposed_origins.

Answer 2

As #KurtFriars mentionned in his answer, I change my controller to :
public function edit(Request $request, $number_canonical)
{
$sample_record = Sample::query()->where('number_canonical', $number_canonical)->first();
$supposed_origins = $sample_record->supposed_origins;
and previous error disappears but I have an other error :
SQLSTATE[42S02]: Base table or view not found: 1146 Table dbname.sample_supposed_origin' doesn't exist`
To have my supposed_origins, It requires also to improve my Sample model like this :
public function supposed_origins() {
return $this->belongsToMany(
'App\SupposedOrigin',
'v3_sample_supposed_origin',
'sample_id',
'supposed_origin_id'
);
}