I have a few real-world (hopefully simple) BCS questions for on-premise database and SharePoint Online (O365) connected by OData web service:
In the scenario where the data source is unavailable/unreachable from the cloud:
(1) What does a user actually see if they try to access an external list in SharePoint while the data source is unreachable?
(2) What does a user actually see for an external data column in a document library (both for a new document and an existing document that had already been tagged with a database value)?
(3) When tagging a document with a database value, is the data actually cached in SharePoint (BDC) or does it strictly live inside of the properties of that document, or is it called every time a user views the properties of that document?
(4) If the data is changed (when SharePoint cannot reach it), what happens to a document that was already tagged with a database value (e.g. a customer name changes from "Customer1" to "Customer2"). Does it automatically update as soon as connectivity is re-established, or is there a synchronization concern I should be aware of.
Thanks in advance!