MySQL

To write efficient Mysql-powered applications a little insight in how Mysql works is needed. One often overlooked example of this is Mysqls silent column changes features, which may cause your tables to look different than you specified. I’m sure most people know, that using chars is generally faster than varchars, but did you know that Mysql may actually change your char-columns to varchars? This happens if you have a variable length column in a table (ie. one varchar and two chars in a table causes all to be converted varchars). You can find more on the automatic column conversions in the Mysql manual.