Oracle 12c新特性：ORACLE自动维护的Schema或默认创建的USER

ORACLE 12c有些小特性非常的实用，如Oracle 12c New Feature: Last Login Time for Non-Sys Users，可以列出非SYS用户的最后登录时间，该数据可以做为清理用户里的依据，同时前段时间应对安全检查， 数据库中扫出了一些弱口令，需要清理一部分长期不登录的用户或找到对应的责任人才可以修改密码，以评估修改修改对系统的影响。 如果找出哪些用户是ORACLE 系统用户在12C之前还是相对麻烦一些，因为我们可能知道像sys, system这些系统默认创建的用户，其它如果安装时选用较多的DB option时，往往不容易查找自动在创建数据库里脚本中创建的哪些用户。

在12c 中dba_user 字典视图引入了ORACLE_MAINTAINED 字段， 当数据库安装options时，oracle自己创建的用户会赋值为”Y”,我们自己创建的用户默认为”N”， 所以像之前的需求在12c中就变的简单，即可以使用LAST_LOGIN判断数据库的最后一次登录，又可以使用ORACLE_MAINTAINED =’N’ 查找我们创建的用户。

同时也可以查出这些schema是否可以exp,expdp,logical standby… , 下面是在我的12.2 CDB测试环境中查询结果

  SQL> SELECT created,
         username,
         oracle_maintained,
         common,
         no_exp,
         no_expdp,
         no_sby,
         default_password,
         sysaux,
         occupant_desc
    FROM dba_users
         LEFT OUTER JOIN (SELECT DISTINCT name username, 'Y' no_expdp
                            FROM sys.ku_noexp_tab
                           WHERE obj_type = 'SCHEMA')
            USING (username)
         LEFT OUTER JOIN
         (SELECT DISTINCT name username, 'Y' no_exp FROM sys.exu8usr)
            USING (username)
         LEFT OUTER JOIN (SELECT DISTINCT name username, 'Y' no_sby
                            FROM SYSTEM.logstdby$skip_support
                           WHERE action IN (0, -1))
            USING (username)
         LEFT OUTER JOIN
         (SELECT DISTINCT user_name username, 'Y' default_password
            FROM sys.default_pwd$)
            USING (username)
         LEFT OUTER JOIN
         (  SELECT schema_name username,
                   'Y' sysaux,
                   DECODE (COUNT (*), 1, MIN (occupant_desc)) occupant_desc
              FROM v$sysaux_occupants
          GROUP BY schema_name)
            USING (username)
ORDER BY created, username;

CREATED	USER	ORACLE MAINTAINED	COM- MON	NO EXP	NO EXPDP	NO SBY	DEF PWD	SYS AUX	occupant_desc
2016-12-09 20:43:28	SYS	Y	YES	Y	Y	Y	Y	Y
2016-12-09 20:43:29	AUDSYS	Y	YES	Y	Y	Y	Y	Y	AUDSYS schema objects
2016-12-09 20:43:29	SYSBACKUP	Y	YES		Y	Y	Y
2016-12-09 20:43:29	SYSDG	Y	YES		Y	Y	Y
2016-12-09 20:43:29	SYSKM	Y	YES		Y	Y	Y
2016-12-09 20:43:29	SYSRAC	Y	YES		Y	Y	Y
2016-12-09 20:43:29	SYSTEM	Y	YES	Y		Y	Y	Y
2016-12-09 20:43:37	OUTLN	Y	YES	Y		Y	Y
2016-12-09 20:52:01	GSMADMIN_INTERNAL	Y	YES		Y	Y	Y
2016-12-09 20:52:02	GSMUSER	Y	YES		Y	Y	Y
2016-12-09 20:52:34	DIP	Y	YES		Y	Y	Y
2016-12-09 20:53:38	XS$NULL	Y	YES		Y	Y	Y
2016-12-09 20:53:57	REMOTE_SCHEDULER_AGENT	Y	YES	Y	Y	Y	Y
2016-12-09 20:53:58	DBSFWUSER	Y	YES	Y	Y	Y	Y
2016-12-09 20:55:20	ORACLE_OCM	Y	YES		Y	Y	Y
2016-12-09 21:00:10	SYS$UMF	Y	YES	Y	Y	Y	Y
2016-12-09 21:04:32	DBSNMP	Y	YES		Y	Y	Y	Y	Enterprise Manager Monitoring User
2016-12-09 21:04:34	APPQOSSYS	Y	YES		Y	Y	Y
2016-12-09 21:05:25	GSMCATUSER	Y	YES		Y	Y	Y
2016-12-09 21:05:30	GGSYS	Y	YES		Y	Y	Y
2016-12-09 21:08:03	ANONYMOUS	Y	YES		Y	Y	Y
2016-12-09 21:08:03	XDB	Y	YES		Y	Y	Y	Y	XDB
2016-12-09 21:24:12	WMSYS	Y	YES		Y	Y	Y	Y	Workspace Manager
2016-12-09 21:26:42	OJVMSYS	Y	YES		Y	Y	Y
2016-12-09 21:30:28	CTXSYS	Y	YES		Y	Y	Y	Y	Oracle Text
2016-12-09 21:31:47	ORDSYS	Y	YES		Y	Y	Y	Y	Oracle Multimedia ORDSYS Components
2016-12-09 21:31:48	MDSYS	Y	YES		Y	Y	Y	Y	Oracle Spatial
2016-12-09 21:31:48	ORDDATA	Y	YES		Y	Y	Y	Y	Oracle Multimedia ORDDATA Components
2016-12-09 21:31:48	ORDPLUGINS	Y	YES		Y	Y	Y	Y	Oracle Multimedia ORDPLUGINS Components
2016-12-09 21:31:48	SI_INFORMTN_SCHEMA	Y	YES		Y	Y	Y	Y	Oracle Multimedia SI_INFORMTN_SCHEMA Components
2016-12-09 21:44:53	OLAPSYS	Y	YES		Y	Y	Y	Y	OLAP Catalog
2016-12-09 21:45:32	MDDATA	Y	YES	Y		Y	Y
2016-12-09 21:48:26	SPATIAL_CSW_ADMIN_USR	Y	YES	Y		Y	Y
2016-12-09 21:55:40	LBACSYS	Y	YES		Y	Y	Y
2016-12-09 21:55:59	DVF	Y	YES		Y	Y	Y
2016-12-09 21:55:59	DVSYS	Y	YES		Y	Y	Y
2017-04-11 17:07:21	C##ANBOB	N	YES	Y

别外也整理了一些在12c之前的版本中可能会创建的SCHEMA及用途， 如下:

User	Password	Purpose	Created by
SYS	CHANGE_ON_INSTALL or INTERNAL	Oracle Data Dictionary/ Catalog	?/rdbms/admin/sql.bsq and various cat*.sql scripts
SYSTEM	MANAGER	The default DBA user name (please do not use SYS)	?/rdbms/admin/sql.bsq
OUTLN	OUTLN	Stored outlines for optimizer plan stability	?/rdbms/admin/sql.bsq
SCOTT	TIGER	Training/ demonstration users containing the popular EMP and DEPT tables	?/rdbms/admin/utlsampl.sql
ADAMS	WOOD
JONES	STEEL
CLARK	CLOTH
BLAKE	PAPER
HR (Human Resources)	HR	Training/ demonstration users containing the popular EMPLOYEES and DEPARTMENTS tables	?/demo/schema/mksample.sql
OE (Order Entry)	OE
SH (Sales History)	SH
DEMO	DEMO	User for Oracle Data Browser Demonstration (last version 9.2)	?/rdbms/admin/demo.sql
ANONYMOUS	invalid password	Used by the PL/SQL gateway that enables a Web browser to invoke a PL/SQL stored procedure through an HTTP listener.	?/rdbms/admin/catqm.sql
AURORA$ORB$UNAUTHENTICATED	INVALID	Used for users who do not authenticate in Aurora/ORB	?/javavm/install/init_orb.sql called from ?/javavm/install/initjvm.sql
AWR_STAGE	AWR_STAGE	Used to load data into the AWR from a dump file	?/rdbms/admin/awrload.sql
CSMIG		User for Database Character Set Migration Utility	?/rdbms/admin/csminst.sql
CTXSYS	CTXSYS	Oracle interMedia (ConText Cartridge) administrator user	?/ctx/admin/dr0csys.sql
DBSNMP	DBSNMP	Oracle Intelligent agent	?/rdbms/admin/catsnmp.sql, called from catalog.sql
DIP	DIP	Generic user account DIP for processing events propagated by DIP. This account would be used by all applications using the DIP provisioning service when connecting to the database	?/rdbms/admin/catdip.sql, called from catproc.sql
DMSYS	DMSYS	Data Mining user	?/rdbms/admin/odmcrt.sql, called from dminst.sql
DSSYS	DSSYS	Oracle Dynamic Services and Syndication Server	?/ds/sql/dssys_init.sql
EXFSYS		User to hold the dictionary, APIs for the Expression Filter	?/rdbms/admin/exfsys.sql, called from catexf.sql from catrul.sql from catproc.sql
LBACSYS	LBACSYS	Label Based Access Control owner when Oracle Label Security (OLS) option is used	?/rdbms/admin/catlbacs.sql, called from catols.sql
MDSYS	MDSYS	Oracle Spatial administrator user	?/ord/admin/ordinst.sql
ORACLE_OCM	ORACLE_OCM	Owner of packages used by Oracle Configuration Manager	?/rdbms/admin/catocm.sql, called from dbmsocm.sql, called from catproc.sql
ORDPLUGINS	ORDPLUGINS	Object Relational Data (ORD) User used by Time Series, etc.	?/ord/admin/ordinst.sql
ORDSYS	ORDSYS	Object Relational Data (ORD) User used by Time Series, etc.	?/ord/admin/ordinst.sql
SI_INFORMTN_SCHEMA		The account that stores the information views for the SQL/MM Still Image Standard. See also ORDPLUGINS and ORDSYS.	?/ord/admin/ordinst.sql
PERFSTAT	PERFSTAT	Oracle Statistics Package (STATSPACK) that supersedes UTLBSTAT/UTLESTAT	?/rdbms/admin/statscre.sql
TRACESVR	TRACE	Oracle Trace server	?/rdbms/admin/otrcsvr.sql
TSMSYS	TSMSYS	User for Transparent Session Migration (TSM) a Grid feature	?/rdbms/admin/cattsm.sql, called from catproc.sql
XDB		Owner of objects for XDB system	?/rdbms/admin/catqm.sql
APEX_030200		Part of the Oracle Application Express Suite – (Oracle APEX, previously named Oracle HTML DB) which is a freeware software development environment. It allows a fast development cycle to be achieved to create web based applications. The account owns the Application Expressschema and metadata. See also APEX_PUBLIC_USER andFLOW_FILES.	?/apex/apexins.sql
APEX_PUBLIC_USER
FLOW_FILES
APPQOSSYS		Used for storing/managing all data and metadata required by Oracle Quality of Service Management.	?/rdbms/admin/catqos.sql
BI		The account that owns the Business Intelligence schema included in the Oracle Sample Schemas. See also HR, OE, SH, IX and PM.	?/demo/schema/bus_intelligence/bi_main.sql
IX
PM
MDDATA		The schema used by Oracle Spatial for storing Geocoder and router data. See also SPATIAL_CSW_ADMIN_USR , SPATIAL_WFS_ADMIN_USR and MDSYS.	?/md/admin/catmd.sql
MGMT_VIEW		An account used by Oracle Enterprise Manager Database Control. Password is randomly generated at installation or database creation time. Users do not need to know this password.	?/sysman/admin/emdrep/bin/RepManager
OLAPSYS		The account that owns the OLAP Catalog (CWMLite). This account has been deprecated, but is retained for backward compatibility.	?/olap/admin/amdsys.sql
ORDDATA		This account contains the Oracle Multimedia DICOM data model.	?/ord/admin/ordisysc.sql
OWBSYS		The account for administrating the Oracle Warehouse Builder repository. Access this account during the installation process to define the base language of the repository and to define Warehouse Builder workspaces and users. A data warehouse is a relational or multidimensional database that is designed for query and analysis. See also OWBSYS_AUDIT.	?/owb/UnifiedRepos/cat_owb.sql
OWBSYS_AUDIT		This account is used by the Warehouse Builder Control Center Agent to access the heterogeneous execution audit tables in the OWBSYS schema.	?/owb/UnifiedRepos/cat_owb.sql
SPATIAL_CSW_ADMIN_USR		The Catalog Services for the Web (CSW) account. It is used by the Oracle Spatial CSW cache manager to load all record type metadata, and record instances from the database into the main memory for the record types that are cached. See also SPATIAL_WFS_ADMIN_USR, MDDATA and MDSYS.	?/md/admin/sdocswpv.sql
SPATIAL_WFS_ADMIN_USR		The Web Feature Service (WFS) account. It is used by the Oracle Spatial WFS cache manager to load all feature type metadata, and feature instances from the database into main memory for the feature types that are cached. See also SPATIAL_CSW_ADMIN_USR , MDDATA and MDSYS.	?/md/admin/sdowfspv.sql
SYSMAN		The account used to perform Oracle Enterprise Manager database administration tasks. The SYS and SYSTEM accounts can also perform these tasks. Password is created at installation or database creation time.	Created as part of the dbconsole or Enterprise Manager build.
WMSYS		The account used to store the metadata information for Oracle Workspace Manager.	?/rdbms/admin/owmctab.plb
WKPROXY	change_on_install	Used to support Oracle’s Ultrasearch option. This feature (and user) was introduced in Oracle9i. The user account IS NOT locked by default is only assigned the “CREATE SESSION” privilege. None the less, this account is not locked by default and Oracle highly recommends that this default password be changed.	?/ultrasearch/admin/wk0csys.sql
WKSYS	change_on_install	Used to support Oracle’s Ultrasearch option. This feature (and user) was introduced in Oracle9i. The user account IS NOT locked by default and as you can see below, is granted the highly privileged role of DBA. Given that this user is granted the DBA role and is not locked by default, Oracle highly recommends that this default password be changed.	?/ultrasearch/admin/wk0install.sql
X$NULL		An internal account that represents the absence of a user in a session. Because XS$NULL is not a user, this account can only be accessed by the Oracle Database instance. XS$NULL has no privileges and no one can authenticate as XS$NULL, nor can authentication credentials ever be assigned to XS$NULL.	?/rdbms/admin/sql.bsq