一、註冊
註冊就是將數據庫作爲一個服務註冊到監聽程序。客戶端不需要知道數據庫名和實例名，只需要
知道該數據庫對外提供的服務名就可以申請連接到數據庫。這個服務名可以與實例名一致，也可以不
一致，且可以註冊多個服務。
註冊可以分爲靜態註冊與動態註冊，下面分別介紹靜態註冊和動態註冊。
二、靜態註冊
靜態註冊就是預先配置好listener.ora文件，配置信息如下：
#listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /u01/app/oracle/product/10.2/db_1)
(PROGRAM = extproc)
)
(SID_DESC =
(SID_NAME = orcl)##數據庫的實例名
(ORACLE_HOME = /u01/app/oracle/product/10.2/db_1)##監聽程序所在路徑
(GLOBAL_DBNAME = test01)##數據庫對外提供的服務名
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = db01)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
)
當用戶通過客戶端申請連接數據庫時，首先通過監聽程序讀取listener.ora中的配置信息(無論數據庫
是否啓動，用戶的連接請求都會通過監聽程序的檢查，因爲靜態監聽是無法識別數據庫的啓動狀態的
，只有用戶試圖連接數據庫時，數據庫纔會返回相關信息。)
下面我們來看下數據庫處於打開和關閉狀態時，服務test01的實例狀態：
1、打開狀態
[oracle@db01 admin]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 16-OCT-2013 06:58:27
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=db01)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date 16-OCT-2013 06:39:09
Uptime 0 days 0 hr. 19 min. 18 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/oracle/product/10.2/db_1/network/admin/listener.ora
Listener Log File /u01/app/oracle/product/10.2/db_1/network/log/listener.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=db01)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "orcl" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "orclXDB" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "orcl_XPT" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "test01" has 1 instance(s).
Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
=>實例orcl的狀態爲unknown
The command completed successfully
此時當用戶通過客戶端連接數據庫時：
SQL> conn system/hat@test01
已連接。
2、關閉狀態：
[oracle@db01 admin]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 16-OCT-2013 06:54:44
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=db01)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date 16-OCT-2013 06:39:09
Uptime 0 days 0 hr. 15 min. 35 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/oracle/product/10.2/db_1/network/admin/listener.ora
Listener Log File /u01/app/oracle/product/10.2/db_1/network/log/listener.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=db01)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "test01" has 1 instance(s).
Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
=>實例orcl的狀態爲unknown
The command completed successfully
此時當用戶通過客戶端連接數據庫時：
SQL> conn system/hat@test01
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux Error: 2: No such file or directory
由此可知，用戶的連接請求通過了監聽的檢查，但數據庫沒有打開，於是就返回了ora-01034的錯誤。
通過上面的實驗，驗證了當監聽靜態註冊時，服務的實例狀態均爲unknown，監聽程序無法知道數據庫
是否處於打開狀態。
三、動態註冊
動態註冊就是不需預先配置listener.ora文件，而是instance在啓動的時候PMON進程根據
init.ora中的instance_name、service_names兩個參數將實例和服務動態的註冊到listener中。
註冊到監聽器中的實例名從init.ora文件中的instance_name參數取得。如果該參數沒有設定值，
那麼它將取init.ora文件中的db_name值。
註冊到監聽器中的服務名從init.ora文件中的參數service_names(該參數可以設置多個值，且值
以逗號分隔)和db_domain取得。如果service_names參數沒有設定值，數據庫將取init.ora文件中的
db_name值。
採取動態註冊時，listener.ora配置如下：
#listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /u01/app/oracle/product/10.2/db_1)
(PROGRAM = extproc)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = db01)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
)
動態註冊默認只註冊到默認的監聽器上(名稱是LISTENER、端口是1521、協議是TCP)，如果需要向
非默認監聽註冊，則只需要配置local_listener參數。
四、如何區分靜態註冊與動態註冊
方法一：通過lsnrctl status監測
靜態註冊的監聽實例狀態爲unknown，動態註冊的監聽實例狀態爲ready
方式二：查看listener.ora文件
listener.ora文件中添加了如下信息的爲靜態註冊，沒有添加爲動態註冊
(SID_DESC =
(SID_NAME = orcl)##數據庫的實例名
(ORACLE_HOME = /u01/app/oracle/product/10.2/db_1)##監聽程序所在路徑
(GLOBAL_DBNAME = test01)##數據庫對外提供的服務名
)
注：1、由於動態註冊監聽是通過pmon進程來動態添加的，因此一旦數據庫關閉，那麼動態註冊的服務便立即從監聽程序中消除。
2、如果想遠程啓動數據庫，需要通過靜態註冊。