There’s a client with one big concern: "What if after a couple of years, I decide to leave ERPNext? What would happen to our database?”
I know backups are in SQL format, but which program can you recommend to read properly these files? It’s important to show my client that he will have a readable backup at any time.
(… sorry, but my knowledge of SQL it’s minimum).
if the client isn’t planning to implement an ERP solution for the long term then it’s not a good idea to implement it in the first place.
HeidiSQL can connect to your DB.
In addition to what @iadr3805 said, I would like to add ERP Next uses MySQL/MariaDB as an RDBMS platform. Therefore its databases are accessible via any client tool/connectivity supported by MySQL client stack (MySQL Workbench, for instance).
The same is true for backups - any MySQL-compliant backup/restore utility will be able to restore the database from such backups.