Data migration scenarios and examples

Note: In the schema defined by the application there are some tables which do not have appropriate candidates for keys that could uniquely identify a record. For example, the CALC_GROUP_VERSION table. Therefore, the migration tool always picks up changes to these tables as new data, therefore migrating even the same migration is possible multiple times. The changes can still be rolled back successfully, if completed in the correct order, which is from the newest to the oldest migration transactions. This returns the database to its initial state.