Pimcore\Model\Element\Tag\Dao::removeTagFromElement PHP Method

    public function removeTagFromElement($cType, $cId)
    {
        $this->db->delete("tags_assignment", "tagid = " . $this->db->quote($this->model->getId()) . " AND ctype = " . $this->db->quote($cType) . " AND cid = " . $this->db->quote($cId));
    }