Well i don't have knowledge about how content exist in Oracle. But below are steps can be done to migrate and in very high level.
1. Extraction – Legacy systems may export content in flat file structures like CSV, XML, etc. In this step, the content is extracted from the source system before further processing.
2. Transformation – In this step, the content is converted or transformed into the format required by the destination. This may involve rewriting links, mapping tags, removing outdated/unwanted information, and special character handling and encoding.
3. Load – This step involves loading the content to the target AEM and is dependent on the transformation step performed earlier. It can be done by using Sling Post Servlet, Content Loader in CRX, or Package Manager
https://www.tothenew.com/blog/content-migration-to-adobe-experience-manager-aem/ - Check this out. You will see similar blogs for the same topic if you google but the overall premise is the same.