Full or Incremental backups with Data Protection for Oracle

Answer

Oracle provides the capability for full and incremental backups (as well as saving the archive redo logs). A full backup is a backup of one (or more) data files that contain all used blocks in that data file. Blocks that have never been used are not backed up. An incremental backup is a backup of one (or more) data files that contain only those blocks that have been modified since a previous backup at the same (or lower) level.
For example: Level 0 is the basis of the incremental backup strategy and backs up all of the used blocks in the Oracle data files. The first Level 1 backup backs up those blocks that have changed since the Level 0 backup. Any subsequent Level 1 backups will back up those blocks that have changed since the previous Level 1 backup.

There is also a cumulative incremental backup (using the 'cumulative' option), which backs up all blocks that have changed since the most recent incremental backup at level N-1 or lower.
For example: Level 0 is the basis of the incremental backup strategy and backs up all of the used blocks in the Oracle data files. The first Level 1 backup backs up those blocks that have changed since the last Level 0 backup. Any subsequent Level 1 backups (with the 'cumulative' option) backs up those blocks that have changed since the original Level 0 backup.

For more information on the types of Oracle incremental backups, consult the Oracle/RMAN documentation.