Changing TimeZone of an Oracle Database I am looking to change the timezone in a quite large Oracle database. What are some of the issues I might run into when trying to change the timezone in this way? 

I don't want to 'trash' the database and am thinking of ways that the database might get trashed by changing TimeZones. 

Any suggestions?
Changing the time zone is described in Oracle Database Globalization Support Guide
11g Release 2 (11.2)