Although I code most of my more complicated projects in Java, I still use 
PHP for simple projects and have many old applications still using it.  When doing database work in PHP I use 
Pear DB to avoid built-in api changes, and because it is very similar to 
Perl DBI as well as many other database abstraction layers which I am already familiar with.
Recently Pear DB has been deprecated in favor of 
Pear MDB2.  DB will continue to be supported with security updates, but new development has moved to MDB2.