Cleaning up your application before attempting to use version control is definitely a good idea!
As we were getting everything setup, we started having Unique Constraint Violations during import (running $base/install.sql with SQL*Plus). After some investigating it became clear that our application’s themes were a bit of a mess. We had multiple themes in the application, which I’m sure isn’t considered a best practice. The themes were 101. Initialized and 3. Business Look.
What happened was, theme 101 defined a Page Template called Login, as did theme 3. During the export split, it creates
for theme 3, then over writes that file when it gets to theme 101. The reason for this is that the export splitter doesn’t anticipate multiple themes, and as such places all page templates in the same directory. Your export’s $base/install.sql will now contain two references to this login.sql — the second time it @includes login.sql you’ll get a unique constraint exception.
Once you know this is the problem, the solution is simple, take the time to cleanup your themes!
I don’t think it’s fair to consider this a bug in the application export splitter, but it could be avoided if it were altered to create using a structure like