Differences between full Oracle backup and zero-level Incremental Backup

More official statements

Full
A backup of a datafile that has des every allocated block in the file being backed up. A full backup of a datafile can be an image copy, in which case every data block is backed up. it can also be stored in a backup set, in which case datafile blocks not in use may be skipped, according to rules in Oracle database backup and recovery reference.

A full backup cannot be part of an incremental backup strategy; that is, it cannot be the parent for a subsequent Incremental backup.

Incremental
An incremental backup is either a level 0 backup, which has des every block in the file has t blocks compressed out because they have never been used, or a level 1 backup, which threads des only those blocks that have been changed since the parent backup was taken.

A level 0 Incremental backup is physically identical to a full backup. the only difference is that the level 0 backup is recorded as an incremental backup in the RMAN repository, so it can be used as the parent for a Level 1 backup.

 

Words found on the Internet

The only difference between a level 0 backup and a full backup is that a full backup is never provided in an incremental strategy. if no level 0 backup exists when you run a level 1 or higher backup, RMAN makes a level 0 backup automatically to serve as the base.

Incremental Backup level 0 and full backup are full backup, but Incremental Backup level 0 uses RMAN backup, only used block is backed up, and used and unused block are backed up completely

 

To sum up, there are two differences between the two.

1

Full backup cannot be used as the basis for level 1 Incremental Backup

2

When RMAN is used for backup, used and unused blocks are fully backed up. If RMAN is used for backup at level 0, only used blocks are backed up.