Over the last few days different people asked me for comments about PHP dropping MySQL support. These questions confused me, but meanwhile I figured out where these rumors come from and what they mean.
The simple facts are: No, PHP is not dropping MySQL support and we, Oracle's MySQL team, continue working with the PHP community.
For the long story we first have to remember what "PHP's MySQL support" includes. There key part are four extensions which are part of the main PHP tree:
The first one, ext/mysql provides the mysql_* functions. This is the classic interface taught in many (old) books and used by lots of (old) software. mysqli is "mysql improved", this is a younger extension providing access to all MySQL features. pdo_mysql contains the driver for PDO, PHP's database API abstraction layer. mysqlnd is the MSQL native driver, this module goes mostly unseen and provides a common set of functionality for the three other modules in order to talk to the MySQL Server.
Additionally we maintain a bunch of PECL extensions plugging into mysqlnd, which I won't mention in detail, the PHP documentation has info on most.
Now that's a lot of code and we an look at what is actually happening:
The old mysql extension, ext/mysql, is old. The code goes back to the early days of PHP and MySQL and embraces some bad design decisions. For example if no explicit connection resource is passed all functions will try to use the last connection which was being used. So given a simple example like this:
<?php
mysql_connect("mysql.eample.com", "user", "password");
mysql_select_db("test");
$result = mysql_query("DELETE FROM t WHERE id = 23");
?>
This might do weird things. Let's assume the connect fails, as the error is not handled the script continues to run and will call mysql_select_db(). This won't directly fail but guess and try to connect to a server (most likely on localhost), if that fails the script still won't terminate but mysql_query() will again guess and try to connect. If all things come together this will suddenly work and the script will operate on a completely different database than expected which can have really bad consequences.
But that's not all. As said the code goes way back, it is grown with PHP and MySQL. It tries to be compatible with all versions of MySQL since at least 3.23 this all makes the code hard to maintain.
When PHP 5.0, which added mysqli, came along in 2004 it was decided that maintaining this is troublesome and that we won't add new features to that old extension but only to mysqli (as well as to pdo_mysql, which came along a bit later in PHP 5.1, as long as it makes sense) We also started to advertise these newer extensions over the old one.
So we lived on for a while, added features to mysqli, fixed a few bugs in mysql, normal operations. Over the time we noticed that people still use the old extension even for new projects and prevent them access from features (i.e. prepared statements or support for multiple result sets as needed for stored procedures etc.) but we also knew that we can't simply deprecate and remove the extension as it is way to commonly used. So in 2012 we started a "soft deprecation" process, which meant to add deprecation warnings to the documentation and suggesting alternatives using mysqli or PDO.
A bit later, with PHP 5.5 which was released in June 2013, it was decided to add such a deprecation notice to the code, so each time a script is connecting to a MySQL server using the mysql extension a deprecation notice would be triggered.
That's the state we are in and there is no date by which the old mysql extension will be removed from PHP. Atsome point in the future. Certainly not the upcoming PHP 5.6, though.
Why not? - Since we are aware of many projects with a long history who can't simply swap this out. One of these projects is Wordpress. And this brings us to the current discussion:
Wordpress is an old project, going back to the days of PHP 4 where there was only the old mysql extension and nothing else. Wordpress also doesn't live on its own but with tons of plugins extending all kinds of features. Some of these go equally long back, many need database access, so many make more or less direct use of ext/mysql. After quite some discussions and heated debate in different channels the Wordpress developers now decided to do the switch. As they are aware of the trouble this causes to the plugin environment they are carefully, though - they actually allow switching between both extensions, mysql and mysqli.
As always such major changes become heated and imprecise statements loose their context and thus wrong messages circulate. So nothing to worry about, while I'd like to encourage all users of the old mysql extension to follow Wordpress and other examples and do the switch.
I hope this helped to clear things up!