src/Leevel/Database/Select.php
protected function unCamelize(string $value, string $separator = '_'): string
    {
        return strtolower(
            preg_replace(
                '/([a-z])([A-Z])/',
                '$1'.$separator.'$2',
                $value
            )
        );
    }
protected function unCamelize(string $value, string $separator = '_'): string
    {
        return strtolower(
            preg_replace(
                '/([a-z])([A-Z])/',
                '$1'.$separator.'$2',
                $value
            )
        );
    }
驼峰转下划线.

@param string $value
@param string $separator

@return string