Is it possible to use data from ArcSDE geodatabases (hosted in Oracle, in this instance) in Portal webmaps? I've been searching documentation and the internet for a while, and it's implied that it's possible, but I can't seem to find a specific instance of it being done or how to do it.
Yes (short answer)
How do I do that? (longer answer)
As @Vince and @Mike comment, the missing piece is "Publishing" a map and feature service(s) to ArcGIS for Server (AGS). So the roadmap is:
- a layer in ArcSDE (backend) gets modeled and populated with data, then
- added to an MXD (desktop) and manipulated until it appears as desired, then
- the Map is "Published" to an ArcGIS Server Map Service (middle-tier if you will) making multiple feature services (matching the MXD contents) available and ALSO referencing them within Portal (or ArcGIS Online), then
- the Map services are managed within Portal Administrator (or AGS Online) to share them with the right groups, etc.
- Applications are developed and deployed which consume these Map services and are based on web-language prototype applications.
Each of these steps are documented to one degree or another, but the high-level roadmap isn't always clear when reading the detailed documentation. Keep this roadmap handy while you review this tutorial (steps 3-4.)