If a resource ID is returned by mysql_query() you have run a valid SQL statement. The resource ID is simply an identifier for your "resource" - in this case a mysql-database. You can use all of PHP4+'s bundled mysql-functions (e.g. mysql_num_rows(), mysql_fetch_array()) etc. to do whatever you require - fetch data, etc. It's all in the PHP Manual.php manual wrote:mysql_query() returns a resource identifier or FALSE if the query was not executed correctly
A general note: if you are creating an online shop: YOU MUST(!!!!) make sure that what you are doing is as secure as possible. That means you know about PHP as well as mySQL security issues (e.g. register_globals, sql injection etc. etc.).
If you plan to write your own credit card transaction script as part of this shop-system: don't unless you can honestly say that you know the ins and outs of the security issues involved. And there are plenty. You'd be dealing with other people's money and one mistake in your script can cost them - and eventually you - a lot of money, time etc.