We recently helped a client migrate from Oracle Database XE to SE2. There was no choice – they had reached the XE 12GB data limit. Going to SE2 is effectively a downgrade because XE has all the EE features, so you would usually do this with Data Pump. But you can’t: the Data Pump export has to create its master table, which is impossible when you are at the 12GB limit. In fact, almost everything you try will fail. Eventually we extracted the schemas with the old legacy exp utility, but there are any number of things that exp cannot handle and I had to write a shed load of code (dbms_metadata…..) to identify and extract all the objects that exp left behind.
The lesson: you must monitor your XE systems, and move off them well before hitting the 12GB limit. Don’t leave it until then.
ps – the move from XE to SE2 included a move from AWS to OCI. That was the easy part.