There are many ways to connect to databases in PHP, whether you use MySQL, Oracle, or some other database. For the past year I have been using ADOdb, a database abstraction layer that is available under the GPL at
ADOdb Database Abstraction Library for PHP (and Python) for MySQL, PostgreSQL, Microsoft SQL Server, Oracle, Firebird, Interbase, LDAP, Access, VFP, DB2 and many other databases. This abstraction layer is extremely easy to learn and extremely powerful. I tried the PEAR database abstraction layer that is in most of the PHP distributions, but this one is just outstanding. It is easy to install and there are plenty of tutorials available on the Internet to get ideas on how to use it. You can call Oracle procedures, insert, update, delete and do many other functions with ease. I would suggest this to anyone that is using PHP to connect to your organization's live instance of Salesforce.com
There are many other tutorials on the internet that are available to connect to salesforce, but I try and write mine extremely simple, in such a manner that a cave man can do it (sure I stole that from GEICO).
If anyone would like to join in the conversation and add new coding snippets or ask a question or rebuke one of my examples, please do. I do not try to make any suggestions that I am the best out there. I am learning new items every day and will continue to post new items as I learn them.
One new item that I am trying to develop today is a real time update to the Accounts object using PL/SQL, PHP with ADOdb and the PHP toolkit. So far testing is slow, but live account updates are now happening in real time when I submit a form on my localhost. I will update or add this when all functionality is tested and the script(s) are working.
Thanks,
Mike