--oracle体系结构1：基本概念

1.ORACLE_BASE

2.ORACLE_HOME

3.ORACLE_SID(set indentifier)

[oracle@localhost ~]$ env |grep ORACLE

ORACLE_SID=orcl

ORACLE_BASE=/home/oracle/app

ORACLE_HOME=/home/oracle/app/oracle/product/11.2.0/dbhome_1

 PFILE:  ?\database\INITorg11g.ORA  ----问号即是表示oracle_home，在windows下面是 E:\app\Administrator\product\11.2.0\dbhome_1\database

                                    ----linux下面是?/

RMB =

  (DESCRIPTION =

    (ADDRESS_LIST =

      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.137.80)(PORT = 1521))

    )

    (CONNECT_DATA =

      (SID = bcd)

    )

  )

CRM=

  (DESCRIPTION =

    (ADDRESS = (PROTOCOL = TCP)(HOST =&&)(PORT = 1521))

    (CONNECT_DATA =

      (SERVER = DEDICATED)

      (SERVICE_NAME =abc)

    )

  )

  )

*.db_name='org11g'

# LISTENER =

#  (ADDRESS_LIST=

#     (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))

#     (ADDRESS=(PROTOCOL=ipc)(KEY=PNPKEY)))    

# SID_LIST_

#   List of services the listener knows about and can connect

#   clients to.  There is no default.  See the Net8 Administrator s

#   Guide for more information.

#

# SID_LIST_LISTENER=

#   (SID_LIST=

#     (SID_DESC=

#                                          #BEQUEATH CONFIG

#          (GLOBAL_DBNAME=salesdb.mycompany)

#          (SID_NAME=sid1)            

#          (ORACLE_HOME=/private/app/oracle/product/8.0.3)

#                 #PRESPAWN CONFIG

#         (PRESPAWN_MAX=20)

#       (PRESPAWN_LIST=

#           (PRESPAWN_DESC=(PROTOCOL=tcp)(POOL_SIZE=2)(TIMEOUT=1))

#         )

#        )

#       )

      ------------------------------------

   <alias>= [ (DESCRIPTION_LIST =  # Optional depending on whether u have

                                                   # one or more descriptions

                                                   # If there is just one description, unnecessary ]

        (DESCRIPTION=

          [ (SDU=2048) ]     # Optional, defaults to 2048

                                          # Can take values between 512 and 32K

          [ (ADDRESS_LIST=    # Optional depending on whether u have

                                          # one or more addresses

                                          # If there is just one address, unnecessary ]

        [ (ADDRESS=

              (PROTOCOL=ipc)

              (KEY=is a standard key used)>)

               )

            )

        [ (CONNECT_DATA=

            (SID=)

            [ (GLOBAL_NAME=) ]

          )

        ]

数据库名：db_name 一般在spfile中会设置，代表的是数据库也就是构成数据库物理文件的总称。

实例名：instance_name 一般是在是由初始化参数中的instance_name决定。如果该参数没有被指定，就会被该用户环境变量ORACLE_SID决定。

全局数据库名：global_dbname是由listenner.ora中指定的，这个名字代表的是客户端连接到数据库时，tnsnames.ora中service_name参数所对应的值。

              数据库通过库链（database link）引用其它数据库时，database的选项中必须填入对方数据库的全局数据库名。

连接字符串：用于在oracle的客户端唯一标识某个特定oracle服务器。连接字符串在tnsnames.ora中设置。

            通常情况下设置的信息包含主机名，实例名，侦听端口号。连接字符串的意义在于告诉客户端以什么样的方式连接到哪儿的oracle数据库管理系统。