How are changes to BDM handled?
Be very careful in using BDM editing...you could cause serious problems...
There is no documentation on the management of BDM's as such, and as you have found out.
If you use the BDM editor in Studio you should be fine if you DO NOT delete things.
Bonitasoft are aware of the issue and have added changes to BDM into their roadmap as documented here:
Adding fields and queries in general works, Deleting fields could cause everything to stop (for that BDM). Changing Indexes may not work.
You would have to edit all your forms and pages and REST calls as well, make sure you have an Asset index of how and where BDM's and fields are used. I know this is facility is not in Community. It would be good to have such a report available :)
Prior to the changes being made by Bonitasoft be aware that Importing a BDM will overwrite the current one. Completely. So if you have two developers make sure they are using the same BDM, exactly the same BDM.
PS: If this reply answers your question, please mark a resolved.
Database DDL on BDM is handled by BonitaBPM platform itself, there's no need to do manual steps outside of Bonita.
Because of this, DB user that Bonita BPM is using to access BDM database must have sufficient permission to run DDL statement.