'array', ]; public function researchProject() { return $this->belongsTo(ResearchProject::class, 'research_project_id'); } public function changeRequest() { return $this->belongsTo(BomChangeRequest::class, 'change_request_id'); } public function costScenario() { return $this->belongsTo(CostScenario::class, 'cost_scenario_id'); } public function documentedBy() { return $this->belongsTo(User::class, 'documented_by'); } }