I've been reading on Episerver, but still have some questions. For instance, if I want to primarily load data from a separate Oracle database (through an API), how would I do that? I mean, the data will not be present in Episerver's local database. Think of this as setting up a website where the data to be displayed is mainly reports, tables of numbers from the Oracle base.
Any advice or tips on what to read up on?
Use standard .NET.
Normally you will build a repository type of class that handles the external communication. Use that repository class from page controller. Extend the view model with the type of data you want to display. Modify view to display it etc..
If you have a lot of business rules, add a service layer. Sounds like you don't need one if you are mainly displaying data.
So standard .NET and MVC basically. Cache what can be cached...
For just showing it's normally fine with a js solution. I normally go server side though. More options for caching, combining from multiple sources, logging, export to excel etc.