Forum Moderators: coopster
hmm, the php.net site, especially the user comments on the bottom, has hours of interesting and in depth reading.
There are the various cookbooks, I have
PHP Cookbook (O'Reilly)
by David Sklar, Adam Trachtenberg
PHP Developer's Cookbook (2nd Edition)
by Sterling Hughes, Andrei Zmievski
as for some of the specific tasks you mentioned
PHP MySQL Functions [ca.php.net]
PHP Oracle 8 functions [ca.php.net]
PHP Oracle functions [ca.php.net]
As far as ecomm etc, that's a tougher one. PHP will do whatever you need but first you have to figure out what it is that you need. ;)