、启动dbconsole
 [oracle@devrfel501 ~]$ emctl start dbconsole
如果提示：OC4J Configuration issue. /opt/oracle/product/10.2.0/oc4j/j2ee/OC4J_DBConsol，则说明没有配置或没有创建
2、配置dbconsole
 [oracle@devrfel501 ~]$ emca -config dbcontrol db
STARTED EMCA at Apr 21, 2009 2:21:41 AM
EM Configuration Assistant, Version 10.2.0.1.0 Production
Copyright (c) 2003, 2005, Oracle.  All rights reserved.
Enter the following information:
Database SID: orcl
Listener port number: 1521
Password for SYS user:
Password for DBSNMP user:
Password for SYSMAN user:
Email address for notifications (optional):
Outgoing Mail (SMTP) server for notifications (optional):
-----------------------------------------------------------------
You have specified the following settings
Database ORACLE_HOME ................ /opt/oracle/product/10.2.0
Database hostname ................ devrfel501
Listener port number ................ 1521
Database SID ................ orcl
Email address for notifications ...............
Outgoing Mail (SMTP) server for notifications ...............
-----------------------------------------------------------------
Do you wish to continue? [yes(Y)/no(N)]: Y
Apr 21, 2009 2:23:52 AM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /opt/oracle/product/10.2.0/cfgtoollogs/emca/orcl/emca_2009-04-21_02-21-41-AM.log.
Apr 21, 2009 2:24:14 AM oracle.sysman.emcp.util.DBControlUtil secureDBConsole
INFO: Securing Database Control (this may take a while) ...
Apr 21, 2009 2:24:35 AM oracle.sysman.emcp.util.DBControlUtil secureDBConsole
INFO: Database Control secured successfully.
Apr 21, 2009 2:24:35 AM oracle.sysman.emcp.util.DBControlUtil startOMS
INFO: Starting Database Control (this may take a while) ...
Apr 21, 2009 2:26:15 AM oracle.sysman.emcp.EMDBPostConfig performConfiguration
INFO: Database Control started successfully
Apr 21, 2009 2:26:15 AM oracle.sysman.emcp.EMDBPostConfig performConfiguration
INFO: >>>>>>>>>>> The Database Control URL is https://devrfel501:5502/em <<<<<<<<<<<
Enterprise Manager configuration completed successfully
FINISHED EMCA at Apr 21, 2009 2:26:15 AM
 
3、查看dbconsole的状态和访问地址
 [oracle@devrfel501 ~]$ emctl status dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.4.0
Copyright (c) 1996, 2007 Oracle Corporation.  All rights reserved.
Oracle Enterprise Manager 10g is running.
------------------------------------------------------------------
Logs are generated in directory /opt/oracle/product/10.2.0/devrfel501_orcl/sysman/log
4、删除数据库的 Database Control配置
oracle@devrfel501 ~]$ emca -deconfig dbcontrol db
 
5、常用的命令语法：
emca -repos create创建一个EM资料库
emca -repos recreate重建一个EM资料库
emca -repos drop删除一个EM资料库
emca -config dbcontrol db配置数据库的 Database Control
emca -deconfig dbcontrol db删除数据库的 Database Control配置
emca -reconfig ports 重新配置db control和agent的端口
emctl start console启动EM console服务，使用前需要先设置ORACLE_SID环境变量
emctl stop console停止EM console服务，使用前需要先设置ORACLE_SID环境变量
注：通过查看$ORACLE_HOME/install/portlist.ini 文件可以知道当前dbcontrol正在使用的端口，默认dbcontrol http端口1158，agent端口3938。如果要重新配置端口，可以使用如下命令：
emca -reconfig ports -dbcontrol_http_port 1159
emca -reconfig ports -agent_port 3939
使用命令行工具emctl可以启动/停止console服务，察看服务状态等
 
下面一个是实际操作的例子:
由于安装oracle的时候没有设置oracle_hostname，oracle oem在%oracle_home%下面产生了两个包含我当时的ip address的目录，192.168.1.112_epcit和oc4j\j2ee\OC4J_DBConsole_192.168.1.112_epcit 这样一旦我的ip address改变了，运行emctl start dbcontrol会报错：
 
C:\>emctl status dbconsole
OC4J Configuration issue. %oracle_home%/oc4j/j2ee/OC4J_DBConsole_%ip%_%sid% not found.
 
只好重新配置database control了。
 
1。数据库和listener都必须已经启动并正常工作。
2。设置系统环境变量oracle_hostname （如果你还没有设置的话）
2。emctl stop dbconsole （如果你的db control还在运行的话）
3。sc delete OracleDBConsoleepcit （删除windows service，不删除好像最后会报错）
4。emca -config dbcontrol db -repos recreate
 
C:\>emca -config dbcontrol db -repos recreate
STARTED EMCA at Feb 6, 2009 2:50:26 PM
EM Configuration Assistant, Version 10.2.0.1.0 Production
Copyright (c) 2003, 2005, Oracle.  All rights reserved.
Enter the following information:
Database SID: epcit
Listener port number: 1521
Password for SYS user: change_on_install
Password for DBSNMP user: change_on_install
Password for SYSMAN user: change_on_install
Email address for notifications (optional):
Outgoing Mail (SMTP) server for notifications (optional):
-----------------------------------------------------------------
You have specified the following settings
Database ORACLE_HOME ................ D:\oracle\product
Database hostname ................ BLC05
Listener port number ................ 1521
Database SID ................ epcit
Email address for notifications ...............
Outgoing Mail (SMTP) server for notifications ...............
-----------------------------------------------------------------
Do you wish to continue? [yes(Y)/no(N)]:y
 
...............
 
确认一切ok，没有出现failed字样。如果有错的话，可以查看%oracle_home%\cfgtoollogs\emca\下面的log文件。
登陆 http://blc05:5500/em  终于又看到了熟悉的页面。