Understanding RMAN Backupset

I feel a bit confused when I read about RMAN!

what are the differences between:

RMAN> backup as backupset

RMAN> backup database;

RMAN> backup database plus archivelog;

RMAN> backup as backupset database include current controlfile;

what is the difference between backup database and backup as backupset

also how to backup the database + needed archivelog + controlfile + spfile in one command for a full restore when needed?

is there any site explains this stuff in details with examples?

RMAN uses backupsets by default. The following commands will create a backup to a backupset:

RMAN> backup database;

RMAN> backup database plus archivelog;

This is assuming that you haven’t changed the default RMAN parameters:

RMAN> SHOW ALL;
...
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default

“Backup as backupset” is not a valid command and will return a syntax error.

“Backup as backupset database include current controlfile” might be useful if you changed the default backup type to something other than a backupset (e.g. “BACKUP TO COPY”).

Source: Database Backup and Recovery Basics

I suppose that you looked at the Oracle site (http://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmquick.htm)? If not then look here: http://www.thegeekstuff.com/2013/08/oracle-rman-backup/.