With the data migration service, if your on prem database is up, how would you reconcile data changes that happen during the migration to the cloud?
This is a great question! Luckily, you will not find that level of detail on the CCP exam. To learn more about how DMS works, please review the official documentation here.
From the official documentation:
AWS Database Migration Service helps you migrate your databases to AWS with virtually no downtime. All data changes to the source database that occur during the migration are continuously replicated to the target, allowing the source database to be fully operational during the migration process. After the database migration is complete, the target database will remain synchronized with the source for as long as you choose, allowing you to switchover the database at a convenient time.
Good luck with the exam!