I get a php yii error:
trying to get property of non-object.
What is wrong?
Here is my code:
public function actiondnyparentchild()
{
    $parentTitleId = $_GET['contentTitleId'];
    $query = 'SELECT contentTitleId, marathiTitle FROM dnycontenttitle WHERE contentTitleId IN
        (SELECT childTitleId FROM dnycontentcategories WHERE parentTitleId='.$parentTitleId.')';
    $resultschild = Yii::app()->db->createCommand($query)->queryAll();
    $mainchild = array();
    foreach($resultschild as $ressubdata)
    {
        $mainchild[] = array(
            "parentId" => $ressubdata->contentTitleId
        );
    } 
    echo "{'contents':".CJSON::encode($mainchild)."} ";  
}
 
    