How to migrate Oracle database to MySQL server?
I recommend to do this migration in two steps.


Use MySQL Workbench to migrate most of the db objects and data to MySQL (table data will be copied by this process too). See Using the MySQL Workbench Migration Wizard for details. This will leave you with manual work for specific objects like stored procedures. No tool can do an automatic migration as stored routines differ vastly between Oracle and MySQL.
Use MySQL Workbench to reverse engineer the migrated db into a model.
Use this model to adjust objects to your new schema structure.
Synchronize the model to your server to apply the changes. Depending on what changes you made this might be non-destructive, but of course, having a backup is always a good idea.


You can repeat steps 3 and 4 as many times as you wish to incrementally adjust your schema. Synchronization will also take over any changes made in schema by others (two way sync).

Migration from Oracle to MySQL is not supported by MySQL Workbench. All my suggestions above are just that, ideas one can try out to get it at least partially working. Nothing of that is being tested, however, because, as I said, Oracle to MySQL migration is not supported.