从oracle9i开始，后台进程PMON自动在监听器中注册初始化参数SERVICE_NAMES中定义的服务名，SERVICE_NAMES默认为db_name.db_dimain。客户端tns配置中SERVICE_NAME的名称必须是SERVICE_NAMES或其中的一个NAME。
1 listenter.ora文件中的 GLOBAL_DBNAME和tnsnames.ora文件SERVICE_NAME的配置一样时，GLOBAL_DBNAME = A, 连接串中的SERVICE_NAME = A,此时就可以连接上数据库。根据tnsnames.ora文件中的连接串中的SERVICE_NAME = A 找到监听器listener.ora中的SID_DESC = (GLOBAL_DBNAME= A)，之后在找到SID_NAME, 来连接到数据库实例。
2listenter.ora文件中的 GLOBAL_DBNAME和tnsnames.ora文件的SERVICE_NAME的配置一样时，tnsnames.ora中的SERVICE_NAME要与参数文件中的SERVICE_NAMES 参数一样或者是其中之一，否则无法通过tns连接到数据库。
tnsnames.ora文件中的service_name 和 listener.oar文件中的GLOBAL_DBNAME一样的情况：
查看tnsnames.ora文件的配置信息：
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>cat tnsnames.ora
# tnsnames.ora Network Configuration File: /opt/oracle/11.2.0/alifpre/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.
YANGDB =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb)
)
)
YANGDB1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb1)
)
)
YANGDB2 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb2)
)
)
YANGDB3 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb3)
)
)
RAC =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.250.7.200)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = rac)
)
)
监听文件中的配置信息：
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>cat listener.ora
# listener.ora Network Configuration File: /opt/oracle/11.2.0/alifpre/network/admin/listener.ora
# Generated by Oracle configuration tools.
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /opt/oracle/11.2.0/alifpre)
(PROGRAM = extproc)
)
(SID_DESC =
(GLOBAL_DBNAME = yangdb)
(ORACLE_HOME = /opt/oracle/11.2.0/alifpre)
(SID_NAME = yangdb)
)
)
yangdb =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
)
)
ADR_BASE_LISTENER = /opt/oracle
参数service_names是静态的，必须重启机器才能够生效。
oracle@rac3:/home/oracle>sqlplus "/as sysdba"
SYS@yangdb-rac3> alter system set service_names='yangdb,yangdb1,yangdb2,yangdb3' scope=both;
System altered.
SYS@yangdb-rac3> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@yangdb-rac3> startup
ORACLE instance started.
Database mounted.
Database opened.
SYS@yangdb-rac3> show parameter service_names
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string yangdb,yangdb1,yangdb2,yangdb3
进行连接测试：
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>sqlplus yang/yang@yangdb1
SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 20 11:12:13 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
YANG@yangdb-rac3> show parameter service_
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string yangdb,yangdb1,yangdb2,yangdb3
YANG@yangdb-rac3> exit
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>sqlplus yang/yang@yangdb2
SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 20 11:57:26 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
YANG@yangdb-rac3> show parameter service_
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string yangdb,yangdb1,yangdb2,yangdb3
YANG@yangdb-rac3> exit
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>sqlplus yang/yang@yangdb3
SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 20 11:57:38 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
YANG@yangdb-rac3> show parameter service_
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string yangdb,yangdb1,yangdb2,yangdb3
YANG@yangdb-rac3> exit
查看监听服务状态，可以知道共有6个监听服务名。
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>lsnrctl service
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 20-OCT-2011 11:59:11
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0
LOCAL SERVER
Service "yangdb" has 2 instance(s).
Instance "yangdb", status UNKNOWN, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0
LOCAL SERVER
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdb1" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdb2" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdb3" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdbXDB" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"D000" established:0 refused:0 current:0 max:1022 state:ready
DISPATCHER < rac3 pid:>>
(ADDRESS=(PROTOCOL=tcp)(HOST=rac3)(PORT=45357))
The command completed successfully
tnsnames.ora文件中的service_name 和 参数文件中的service_name不一样的情况：
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>vi tnsnames.ora
# tnsnames.ora Network Configuration File: /opt/oracle/11.2.0/alifpre/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.
lily = ----连接标识，可以为任意值
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = lily)
)
)
YANGDB1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb1)
)
)
YANGDB2 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb2)
)
)
YANGDB3 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb3)
)
)
"tnsnames.ora" 60L, 1198C 已写入
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>vi listener.ora
# listener.ora Network Configuration File: /opt/oracle/11.2.0/alifpre/network/admin/listener.ora
# Generated by Oracle configuration tools.
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /opt/oracle/11.2.0/alifpre)
(PROGRAM = extproc)
)
(SID_DESC =
(GLOBAL_DBNAME = lily)
(ORACLE_HOME = /opt/oracle/11.2.0/alifpre)
(SID_NAME = yangdb)
)
)
yangdb =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
)
)
ADR_BASE_LISTENER = /opt/oracle
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>lsnrctl status
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 20-OCT-2011 10:58:30
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date 27-SEP-2011 21:47:16
Uptime 22 days 13 hr. 11 min. 14 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/oracle/11.2.0/alifpre/network/admin/listener.ora
Listener Log File /opt/oracle/diag/tnslsnr/rac3/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rac3)(PORT=1521)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "yangdb" has 2 instance(s).
Instance "yangdb", status UNKNOWN, has 1 handler(s) for this service...
Instance "yangdb", status READY, has 1 handler(s) for this service...
Service "yangdb1" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Service "yangdb2" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Service "yangdb3" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Service "yangdbXDB" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
The command completed successfully
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>lsnrctl service
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 20-OCT-2011 10:58:37
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0
LOCAL SERVER
Service "yangdb" has 2 instance(s).
Instance "yangdb", status UNKNOWN, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0
LOCAL SERVER
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdb1" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdb2" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdb3" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:4 refused:0 state:ready
LOCAL SERVER
Service "yangdbXDB" has 1 instance(s).
Instance "yangdb", status READY, has 1 handler(s) for this service...
Handler(s):
"D000" established:0 refused:0 current:0 max:1022 state:ready
DISPATCHER < rac3 pid:>>
(ADDRESS=(PROTOCOL=tcp)(HOST=rac3)(PORT=45357))
The command completed successfully
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>lsnrctl reload
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 20-OCT-2011 10:58:45
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
The command completed successfully
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>
更改tnsnames.ora文件中的service_name的值 yangdb为lily，并相应的修改listener.ora文件中的global_dbname的值为lily ，也可以成功连接数据库。
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>vi tnsnames.ora
# tnsnames.ora Network Configuration File: /opt/oracle/11.2.0/alifpre/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.
lily =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = lily)
)
)
YANGDB1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb1)
)
)
YANGDB2 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb2)
)
)
YANGDB3 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = yangdb3)
)
)
"tnsnames.ora" 60L, 1196C 已写入
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>sqlplus yang/yang@lily
SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 20 11:00:11 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
YANG@yangdb-rac3> show parameter service_
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string yangdb,yangdb1,yangdb2,yangdb3 --动态监听里面没有lily 这样的服务
YANG@yangdb-rac3> exit
说明：如果 参数文件中的service_names没有lily这个值，但是listener.ora文件中有与之对应的GLOBAL_DBNAME，并且已经启动了静态监听服务，则sqlplus通过@lily也可以连接数据库。
如果没有启动静态监听，即没有lily 这样的service,则不可以连接数据库，(当然修改过之后没有执行reload 或没有重启监听，则还可以连接，因为之前存在，这样的例子不讨论)
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>vi listener.ora
# listener.ora Network Configuration File: /opt/oracle/11.2.0/alifpre/network/admin/listener.ora
# Generated by Oracle configuration tools.
# SID_LIST_LISTENER =
# (SID_LIST =
# (SID_DESC =
# (SID_NAME = PLSExtProc)
# (ORACLE_HOME = /opt/oracle/11.2.0/alifpre)
# (PROGRAM = extproc)
# )
# (SID_DESC =
# (GLOBAL_DBNAME = lily)
# (ORACLE_HOME = /opt/oracle/11.2.0/alifpre)
# (SID_NAME = yangdb)
# )
# )
yangdb =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac3)(PORT = 1521))
)
)
ADR_BASE_LISTENER = /opt/oracle
编辑过之后重新启动数据库（可选），重启监听，目的重新注册服务，去掉静态监听的服务。
SYS@yangdb-rac3> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@yangdb-rac3> startup
Database mounted.
Database opened.
SYS@yangdb-rac3>
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>lsnrctl start
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 20-OCT-2011 11:11:24
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Starting /opt/oracle/11.2.0/alifpre/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 11.2.0.1.0 - Production
System parameter file is /opt/oracle/11.2.0/alifpre/network/admin/listener.ora
Log messages written to /opt/oracle/diag/tnslsnr/rac3/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rac3)(PORT=1521)))
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date 20-OCT-2011 11:11:24
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/oracle/11.2.0/alifpre/network/admin/listener.ora
Listener Log File /opt/oracle/diag/tnslsnr/rac3/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rac3)(PORT=1521)))
The listener supports no services --没有静态监听服务，这时只能通过动态监听的服务来连接到数据库。
The command completed successfully
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>sqlplus yang/yang@lily
SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 20 11:11:35 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor --报错，监听没有lily这样的服务
Enter user-name: ^[[
--通过pmon动态监听的服务名来连接数据库。
oracle@rac3:/opt/oracle/11.2.0/alifpre/network/admin>sqlplus yang/yang@yangdb1
SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 20 11:12:13 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
YANG@yangdb-rac3> show parameter service_
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string yangdb,yangdb1,yangdb2,yangdb3