protected function escapeParameters()
    {
        $parameters = $this->parameters;
        foreach ($parameters as $k => $v) {
            switch (gettype($v)) {
                case 'string':
                    $parameters[$k] = $this->stringEscape($v);
                    break;

                case 'boolean':
                    $parameters[$k] = ($v === true) ? 1 : 0;
                    break;

                case 'object':
                    $parameters[$k] = $this->stringEscape(serialize($v));
                    break;

                case 'array':
                    $parameters[$k] = $this->stringEscape(serialize($v));
                    break;

                default:
                    $parameters[$k] = ($v === null) ? 'NULL' : $v;
                    break;
            }
        }

        return $parameters;
    }