oracle官方文档之PredefinedUserAccounts

搜索oracle 11.2官方文档：mgmt_user http://docs.oracle.com/cd/E11882_01/network.112/e36292/authorization.htm#DBSEG99887 MGMT_USER Grants the SELECT privilege on the different views used for the SYSMAN schema. 搜索oracle 11.2官方文档：SYSMAN

搜索oracle 11.2官方文档：mgmt_user

MGMT_USER

Grants the SELECT privilege on the different views used for the SYSMAN schema.

搜索oracle 11.2官方文档：SYSMAN

SYSMAN

The account used to perform Oracle Enterprise Manager database administration tasks. Oracle Enterprise Manager Grid Control Basic Installation Guide

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SYSMAN

The account used to perform Oracle Enterprise Manager database administration tasks.（执行 oem组件的数据库管理任务）

Oracle Enterprise Manager Grid Control Basic Installation Guide

注释：
oracle数据库里这些预定义的用户，oracle公司设计oracle数据库软件时就已经将这些预定义的用户分类，不同用户执行不同任务。而让不同用户执行不同任务，这个问题不是一个技术（设计）问题，而是一个业务逻辑设计问题。当初设计oracle数据库软件时创建的用户 SYSMAN 就是用于执行 oem组件的数据库管理任务的。 SYSMAN 的角色之一为 MGMT_USER 。
总之，不同预定义数据库用户，oracle公司设计oracle数据库软件时就已经将它们分类规定用于不同用途，这是人为规定的。一旦规定了某一个预定义数据库用户用于某种用途，就会根据这个用途的需要分配该（预定义）数据库用户特定的权限。而不是因为有了某种权限，而有了某种用途。谁因谁果不要颠倒，在逻辑理解上。

Predefined User Accounts

Predefined User Accounts Oracle Database includes several predefined user accounts. The three types of predefined accounts are: Administrative accounts ( SYS SYSTEM SYSMAN and DBSNMP ) SYS and SYSTEM are described in "About Database Administrator

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Predefined User Accounts

Oracle Database includes several predefined user accounts. The three types of predefined accounts are:

Administrative accounts ( SYS , SYSTEM , SYSMAN , and DBSNMP )

SYS and SYSTEM are described in "About Database Administrator Security and Privileges". SYSMAN is used to perform Oracle Enterprise Manager administration tasks. The management agent of Enterprise Manager uses the DBSNMP account to monitor and manage the database. You must not delete these accounts.

Sample schema accounts

These accounts are used for examples in Oracle Database documentation and instructional materials. Examples are HR , SH , and OE . You must unlock these accounts and reset their passwords before using them.

Internal accounts.

These accounts are created so that individual Oracle Database features or components can have their own schemas. You must not delete internal accounts, and you must not attempt to log in with them.