Jeff ShanerAndrew Hargreaves
It's true that the related tables can be added as external datasources.
But there's a problem, for example, you have a list widget using the external datasource, and you have a map widget as well in the OD. the list widget and the map widget are not linked, no feature actions will be working in the list widget! In the real case, this kind of the dashboard could be confusing and misleading.
To make the related table and the map widget work together, as Ted Chapin mentioned in his post, you need to develop a custom widget, in the widget (let's say a list widget built in JavaScript)
1. Use the map widget as the datasource
2. Query the related table directly, Featurelayer.queryFeatures(...), something like that, and make sure to configure your widget so that it can use your dashboard credential to do the query, otherwise it will ask you for credentials.
3. Append the fields from the related table to the map layer features when building the store for the list.
4. After step 3, when building the list, you can determine which fields to display, from the related table or from the layer.
5. Now the list widget and the map is linked. you can use highlight, zoom to , and so on feature actions.
The reason this trick will work is that the featureactionFeatures don't care what you display in the list, as long as you keep the datasourceproxy and IDs of the features, the predefined featureactions will work.
This solution is far from perfect, this twist make me feel I am hacking the system.
Hope ESRI can give us an update for the OD, and let it support related tables, then we can have a more elegant solution.
Cheers,
Simo