Yeah. Part of my confusion is due to Heroku providing a Data Links service that handles a lot of the internal details around establishing a foreign server connection, and not knowing exactly what to expect.
I experimented with IMPORT FOREIGN SCHEMA in a couple of test databases and noticed that there was no declaration of primary key brought over to the local database. So, this is something ActiveRecord simply won't be able to handle right now, and I have to take care of that myself, which is easy enough to do.
The foreign table has a primary key. Ruby on Rails uses a system query to lookup what the primary key on the table is, but it's querying the local database, and not finding anything. In a schema dump of the local database, I don't see a primary key defined, so I'm presuming I need to issue an ADD CONSTRAINT command against the foreign table to reflect what is actually true in the foreign table? Is that correct?
The documentation says doing what you suggest won't work...
