public function addField($name, $dataType = "varchar(255)")
    {
        if ($name == "") {
            throw new Exception("Field name cannot be empty.");
        }

        // Check if the name whether is satisfied
        if (ctype_upper($name[0])) {
            throw new Exception("Field name cannot start with upper-case.");
        }

        $this->fieldList[$name] = new Field($this, $name, $dataType);
    }