I have been looking during hours for a way to check in a database into source control. My first idea was a program for calculating database diffs and ask all the developers to i
Oracle SQL Developer has a "Database Export" function. It can produce a single file which contains all DDL and data.
Have you tried Oracle's Workspace Manager? Not that I have any experience with it in a production database, but I found some toy experiments with it promising.
Don't try to diff the data. Just write a trigger to store whatever-you-want-to-get when the data is changed.