I once had a client that runs a small business, and they have a WordPress website that uses MySQL database and its DBMS.
The first step before I start working was to back up everything (database included) to stay safe in case something goes wrong.
There was a plugin that I used to back up the database and the website files. The plugin was called UpdraftPlus. It is a free plugin that can be installed on any WordPress website. It can be used to back up the website files and the database.
I started a local environment to start developing, and I used MySQL Workbench to connect to my local database; and used the backup file to load some data into the database.
Usually, all DMBSs have backup and recovery software that automatically backs up data periodically. For example, MySQL has a built-in backup and recovery software called MySQLDump. It can be used to back up the database and restore it in case of a failure.
The policies of the backup are different and sometimes controlled by the user; like how many backups should be kept; how often should the backup be taken; and how long should the backup be kept.
There is also a security risk that the backup files must be in a separate location from the database files in case of a security breach or natural disaster.
Backups can be incremental, or full. Incremental backups only back up the changes that have been made since the last backup and then append them to the previous backup file. Full backups back up the entire database every time.
Some serious businesses went too far that for every write operation, a background process is started to replicate these changes across all databases almost in immediate time. This means that there are always numerous copies of the database available.