AWS Database Migration Service (AWS DMS) helps you migrate databases to AWS easily and securely. The AWS Database Migration Service can migrate your data to and from most widely used commercial and open-source databases. The service supports homogenous migrations such as Oracle to Oracle. It also supports heterogeneous migrations between different database platforms, such as Oracle to Amazon Aurora or Microsoft SQL Server to MySQL. The source database remains fully operational during the migration, minimizing downtime to applications that rely on the database.
For more details you can view the following link:-
https://aws.amazon.com/blogs/database/migrating-oracle-database-from-on-premises-or-amazon-ec2-instances-to-amazon-redshift/