quick checkpoints for development mode

i'm a programmer, not a dba. i need a mechanism to quickly make a snapshot of a database (oracle 11g XE) before i run migration. migration changes data, grants, DDL (tables, triggers, lexers, views etc). in case migration fails, i want to quickly revert to the saved state. all this will be done on non-production environment. it's just to speed up the development process i've heard about full backups, flashbacks, snapshots but i have no idea what's the difference and which one is best for my task