How to migrate Oracle Database RDS from AWS to another Cloud using DMS e SCT ?

I apologize, but there seems to be a misunderstanding in your question. AWS Database Migration Service (DMS) and AWS Schema Conversion Tool (SCT) are designed primarily for migrations to AWS, not from AWS to other cloud providers. These tools are specifically built to facilitate migrations into AWS environments.

For migrating an Oracle RDS database from AWS to a PostgreSQL instance on another cloud provider, you would need to use a different approach. Here's a general outline of how you might proceed:

1. Use AWS native tools to export your Oracle RDS data. This could involve creating a backup or dump of your database.

2. Convert the schema and code objects from Oracle to PostgreSQL format. While you can't use AWS SCT directly for a non-AWS target, you might be able to use it to generate conversion scripts that you can then apply manually to your target PostgreSQL database.

3. Set up a PostgreSQL instance on your target cloud provider.

4. Import the converted data and apply the converted schema to your new PostgreSQL instance.

5. Validate the data and functionality in the new environment.

For the actual data transfer and conversion process, you may need to use third-party tools or open-source solutions that support cross-cloud migrations. Alternatively, you could set up a temporary EC2 instance to run your own migration scripts or tools.

Remember that migrating between different database engines (Oracle to PostgreSQL) involves not just data transfer but also schema and code conversion, which can be complex. You'll need to carefully test and validate all database objects and application interactions after the migration.

Lastly, ensure you comply with all licensing and data transfer regulations when moving data between cloud providers.
Sources
Migrating an Oracle Database to PostgreSQL - Database Migration Guide
Refactoring recommendations - AWS Prescriptive Guidance
Migrate an Oracle database to Aurora PostgreSQL using AWS DMS and AWS SCT - AWS Prescriptive Guidance
AWS Schema Conversion Tool - Amazon Web Services