In what cases should data be transferred between databases?

Data transfer between databases is usually performed in the following cases:

• Migration to a new system: when changing the DBMS or the database structure, and existing data needs to be transferred.
• Backup and recovery: transferring data to create backups or restore after failures.
• Data consolidation: when merging multiple applications or databases.
• Data separation: for performance or security reasons, data may be transferred to separate databases.
• Schema update: if a new version of the application requires a different data structure.

In Android, data transfer between databases may be necessary, for example, during app updates when the format of the local database (SQLite) changes or when switching to another storage technology (e.g., Room). It is important to ensure data integrity and correctness during such transfers.