PHP 5 and later can work with a MySQL database using: MySQLi extension (the "i" stands for improved) PDO (PHP Data Objects) Earlier versions of PHP used the MySQL extension. However, this extension was deprecated in 2012.
In at least php-5.3 (linux-126.96.36.199) a process owned by apache could make a link() in a directory owned by apache, to a file owned by webmaster to which it had group read permissions. In php-7.0 (linux-4.13.16) that results in a "permission denied". The link starts at the source anchor and points to the destination anchor, which may be any web resource, for example, an image, an audio or video clip, a PDF file, an HTML document or an element within the document itself, and so on. By default, links will appear as follow in most of the browsers: An unvisited link is underlined and blue. This page shows how to make HTML button links with onclick and href using the