ldc-dam/app/Models/Recherche.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Recherche extends Model
{
    /**
     * The attributes that should be cast.
     *
     * @var array
     */
    protected $casts = [
        'filters' => 'object'
    ];

    // * RELATIONSHIPS

    /**
     * BelongsTo sujet relation
     *
     * Get the sujet that owns the recherche.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function sujet()
    {
        return $this->belongsTo(Sujet::class, 'sujet_id');
    }

    /**
     * BelongsTo user relation
     *
     *  Get the user that owns the recherche.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function user()
    {
        return $this->belongsTo(User::class, 'user_id');
    }
}