Also, if you're starting out doing web application development, read "MySQL and Perl for the Web". That site contains a slick WebDB.pm that does some input validation based on the MySQL table "metadata". (read the book for explanation how to use it :) Actually he (Paul DuBois) has a really excellent book called "MySQL" (I used it to figure out how to do MySQL stuff from the Apache C API, which made me feel special, hehe).