I am doing an e-commerce CMS and all my SQL queries are mysql_* functions. Since they are getting obsolete, I would like to incorporate PDO's/prepared statement.
From a security perspective, should I only use PDO's/prepared statement for queries which involve user input? Can I just use mysql_* functions for queries that don't have user input in them?
Also, I've been googling "PDO vs prepared statement" with no success, to see what the differences are. Is there any difference at all or are they the same thing?
I've also been advised to use MySQLi. Can I stick to PDO's without MySQLi?
Thanks a lot for your suggestions. Regards