app/Models/CharacteristicApproverMaster.php

@@ -40,4 +40,9 @@ class CharacteristicApproverMaster extends Model
     {
         return $this->belongsTo(Machine::class);
     }
+
+    public function requestCharacteristics()
+    {
+        return $this->hasMany(RequestCharacteristic::class, 'characteristic_approver_master_id');
+    }
 }