Which backup type includes all changes made since the last full backup?

A differential backup is characterized by its function of including all changes that have occurred since the last full backup. In other words, every time a differential backup is executed, it retains all the data that has been changed or added since the initial full backup, allowing for recovery of all altered data up to the point of the last differential backup.

This method is particularly effective for restoring data because it simplifies the recovery process. When you need to restore from a differential backup, you only need the last full backup and the last differential backup, making it quicker than recovering from multiple incremental backups, which would require restoring all previous sets.

The other types of backups serve different purposes. For example, an incremental backup only includes changes made since the last backup of any type (full or incremental), which means the restoration process may be more complex and time-consuming if multiple backups need to be combined. A full backup captures all data at a given point in time but does not track changes over time, while online backup refers to data being backed up in real-time to a cloud service, which doesn't define its methodology like differential or incremental does.