I started developing small applications using Oracle XE 10g/11g using APEX. They are intented to be run on desktop computers that acts as a server in small offices. Oracle XE is well suited for those scenarios.
The problem I am facing is in my developing environment where I am not sure how to set up. I have each different system organized as a set of schemas in Oracle XE and that is working fairly good. My problem is the following:
I need to make some serious customization to one of those systems for a new client, but I need to keep a copy of the system as it is right now (support/maintenance) because I have other clients which are using it.
I would like some advice in how to organize this development environment because I'll be facing this problem more than once.