[Typo3] alias length

[Andy Pailthorpe]

Does anyone know how to increase the length of the page alias field?  I am using version 3.5.0, and need a page alias longer than 20 characters.  I can change the database field but this still doesnt allow me to type a longer alias in via the typo3 interface.  Also if i change the database is it likely to have any effects on the rest of typo3?  thanks for your help