To OP: when re-importing your database with another method (the mailing assistant for instance), you must reinsert all your fields one by one from the newly imported database. As your ODT will still look for the older database name when referencing its fields if you don’t do so (hoover your mouse over your fields and the complete field path will pop up). As a workaround, you can also use the database manager (Tools > Options > Libre Office Base) in order to rename your newly imported database to the same name as the older one (don’t rename the ODB file, you have to open the database manager and change the display name only).
I’m adding in my feedback as we currently experience the same issue at the organization I work for. The typical scenario is any machine running Libre Office 6 (Windows or Linux, it doesn’t matter) will lose its connection to a database imported from an ODS file at some point:
- either during adding the fields into an ODT document (you can see the database vanish live right in front of your powerless eyes)
- or after inserting a custom field (unrelated to the database), right after closing the custom field dialog
- or while attempting to delete some text
- or after restarting Writer or any Libre Office application
The database is simply not there anymore, whether from the “data sources” window (Ctrl+Shift+F4) or the database manager (Tools > Options > Libre Office Base), without any manual intervention. I noticed this behaviour started to appear from version 6.0.0.0 alpha onwards and still persists with latest evolution build (6.2.2 as I’m writing this), according to my tests.
On the other hand, Libre Office 5.4.7 works perfectly and doesn’t disconnect an imported-from-ODS database (using the “Exchange database” function) at random.
One workaround I’ve found is going into the database manager and renaming the freshly imported database to something other than its original name. It did work multiple times in my own case but I had reports that even the renaming trick failed at times.
I’m quite puzzled to see nobody else using Libre Office 6 reported that problem before us. This is extremely penalizing and made us ditch Libre Office completely (at least version 6, but at the IT desk I work for, we decided to install Open Office instead, to prevent any further problem we might have missed).
Edit: I even filed a bug describing the issue: https://bugs.documentfoundation.org/show_bug.cgi?id=124680