Generally, data cannot be exported or imported between heterogeneous databases due to the different data formats involved. However, if the data formats are compatible, table data can, in theory, be migrated between them.
Third-party software is usually required for data replication to export and import between heterogeneous databases. For example, you can use a third-party tool to export table records from Oracle into a .txt file. Then, you can use LOAD statements to import the exported table records to a DB engine supported by RDS.