Summary of the differences between sys and system in Oracle

1.
SYS users have DBA permissions, have SYS mode, and can only log into the database through SYSDBA. Is the most authorized account in the Oracle database
SYSTEM has DBA permissions. But there are no SYSDBA permissions. Normally 1 general use this account management database is ok.
2.
(1) sys -- sysdba
system --sysoper
(2) startup/shutdown/dba management can do both

(3) sys has a data dictionary (dictionay), or dictionay belongs to sys schema

(4) sysdba has one more privilege than sysoper
3.
SYSDBA
Perform STARTUP and SHUTDOWN operations
ALTER DATABASE: open, mount, back up, or change character set
CREATE DATABASE
CREATE SPFILE
ARCHIVELOG and RECOVERY
Includes the RESTRICTED SESSION privilege
Effectively, this system privilege allows a user to connect as user SYS.
SYSOPER
Perform STARTUP and SHUTDOWN operations
CREATE SPFILE
ALTER DATABASE OPEN/MOUNT/BACKUP
ARCHIVELOG and RECOVERY
Includes the RESTRICTED SESSION privilege
This privilege allows a user to perform basic operational tasks, but without the ability to look at user data