Thank you for writing to Aspose support team.
There is a detailed article about saving and retrieving documents to database. You may please follow this article
which provides complete detail of saving data to database. Although it is using Document object, you may just replace it with MailMessage or MapiMessage. Rest all the features are as per your requirement.
I am afraid that Aspose.Email does not provide any viewing control, therefore you may please use Outlook via Interop or some other mail client for displaying the message for approval after fetching it from database as described in the above mentioned article. This article is using database syntax which can be used with Oracle as well.
Please feel free to write us back if you have any other query in this regard.