Importing directly into the portal's table should work.
If you only see one record in the portal after import and you expect to see several records, you'll need to do some checking to see what else didn't work.
- Did all the imported records in the portal get the correct values in the table's key fields so that they are correctly linked to the parent record? (Do the import into the portal's table, then immediately use table view to examine all the fields of all the records just imported while they still form the found set for this table.)
- Did a validation rule keep the data for additional records from being imported into this table? (Check the message that pops up after import is complete to see if it says that all records were imported. Check to make sure that a unique values setting on the foreign key or some other field isn't filtering out subsequent records with the same value.)
- Make sure you've selected the correct options when importing.
I'm still unsuccessful and at this point am re-entering the data manually.
For curiosity sake, even though I will ensure never to refresh the portal again but you never know who will come after me, could you please give me an example of what you mean when you said "Did all the imported records in the portal get the correct values in the table's key fields so that they are correctly linked to the parent record?"
I had all the contactID numbers imported, which is what I assume you mean, so other than that I don't know what went wrong.
If your relationship is:
MainTable::ContactID = ImportTable::ContactID
Go To a layout where you can list all the records from ImportTable and where you can put the cursor directly in the ImportTable::ContactID field.
Check to make sure that you see the values you expect to see here in all the records. Click into the field to confirm that no invisible characters where imported such that the values look like they match but don't actually match.
If my tables were related by more than just contactID would that cause a problem?
It might. It will change the criteria by which the values match between the two tables and this will change what is displayed in the portal. Can't say much more without knowing what relationship you've set up here...
Good news, it works now! Bad news, I don't know what I did to fix it!
I made a copy of the database and cut the relationship down to contactID::contactID. I also clicked on the the checkbox that asks whether FM should assign ID, and unchecked one of the source fields.
Problem is that I've been trying to recreate the problem, to find out exactly what made the difference, by undoing all of that and it's STILL working! I don't know what happened. Sorry that this isn't more helpful. But thank you very much PhilModJunk because your suggestions lead to success in the end!