1.

SYS用戶具有DBA權(quán)限，并且擁有SYS模式，只能通過SYSDBA登陸數(shù)據(jù)庫。是Oracle數(shù)據(jù)庫中權(quán)限最高的帳號

SYSTEM具有DBA權(quán)限。但沒有SYSDBA權(quán)限。平常一般用該帳號管理數(shù)據(jù)庫就可以了。

2.

（1）sys -- sysdba

system --sysoper

（2）startup/shutdown/dba管理兩個(gè)都能做

（3）sys擁有數(shù)據(jù)字典(dictionay),或者說dictionay屬于sys schema

（4）sysdba比sysoper多了一個(gè)create database的權(quán)限

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

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