Model中如何使用mysql函数

INSERT INTO point ( point,text ) VALUES ( PointFromText ( ‘POINT(1 1)’ ),‘第一个点’);

$model = new point();
$model->point=PointFromText ( ‘POINT(1 1)’ ;
$model->text=‘第一个点’;
$model->save();

Call to undefined function addons\JohoShop\backend\controllers\PointFromText ();