实验目的：在虚拟机中用sqlplus工具访问真实机的数据库；
实验环境：
真实机（windows系统，数据库服务名 orcl）：
SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Prod
PL/SQL Release 10.2.0.3.0 - Production
CORE 10.2.0.3.0 Production
TNS for 32-bit Windows: Version 10.2.0.3.0 - Production
NLSRTL Version 10.2.0.3.0 - Production
虚拟机（linux系统，数据库服务名 yjgocp）：
SQL> select * from v$version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
PL/SQL Release 11.2.0.1.0 - Production
CORE 11.2.0.1.0 Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
sqlplus登录本地及远程数据库的方式有：
sqlplus username/password
sqlplususername/password@net_service_name
sqlplus username/password assysdba
sqlplususername/password@//host:port/sid
在虚拟机上操作,直接链接真实机数据库
[oracle@localhost ~]$ sqlplusscott/tiger@orcl
SQL*Plus: Release 11.2.0.1.0 Production onSun Jul 28 13:40:38 2013
Copyright (c) 1982, 2009, Oracle. All rights reserved.
ERROR:
ORA-12154: TNS:could not resolve theconnect identifier specified
说明链接信息配置有问题，查看本地环境变量及查找本地tnsname.ora
[oracle@localhost ~]$ more .bash_profile
# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
# User specific environment and startupprograms
PATH=$PATH:$HOME/bin
export ORACLE_BASE=/u01/app/oracle
exportORACLE_HOME=/u01/app/oracle/product/11g
export ORACLE_SID=yjgocp
export NLS_LANG=AMERICAN_AMERICA.ZHS16GBK
export PATH=$ORACLE_HOME/bin:$PATH
[root@localhost script]#find / -name tnsname*
/u01/app/oracle/product/11g/inventory/Templates/hs/admin/tnsnames.ora.sample
/u01/app/oracle/product/11g/network/admin/samples/tnsnames.ora
/u01/app/oracle/product/11g/hs/admin/tnsnames.ora.sample
TNS_ADMIN
This variable TNS_ADMIN specifies the user ID of the OracleNet Services configuration files, for example, LISTENER.ORA, TNSNAMES.ORA and SQLNET.ORA. If TNS_ADMIN is not defined, then the configuration files are searched underthe local user ID with the prefix NETWORK.ADMIN.
环境变量里面没有设置该值，说明oracle 会到默认的network/admin/下查找LISTENER.ORA, TNSNAMES.ORA and SQLNET.ORA文件，如果想链接远程数据库，那么需要在该位置创建一个TNSNAME.ORA文件，并把远程的链接信息配置到该文件中；
经过刚才查找得之/u01/app/oracle/product/11g/network/admin/samples/tnsnames.ora把该文件拷贝到/u01/app/oracle/product/11g/network/admin/目录下一份，
然后添加远程数据库的链接信息：
[oracle@localhost admin]$ more tnsnames.ora
# This file contains the syntax informationfor
# the entries to be put in any tnsnames.orafile
# The entries in this file are need based.
# There are no defaults for entries in thisfile
# that Sqlnet/Net3 use that need to beoverridden
#
# Typically you could have two tnsnames.orafiles
# in the system, one that is set for theentire system
# and is called the system tnsnames.orafile, and a
# second file that is used by each userlocally so that
# he can override the definitions dictatedby the system
# tnsnames.ora file.
# The entries in tnsnames.ora are analternative to using
# the names server with the onames adapter.
# They are a collection of aliases for theaddresses that
# the listener(s) is(are) listening for adatabase or
# several databases.
# The following is the general syntax forany entry in
# a tnsnames.ora file. There could beseveral such entries
# tailored to the user's needs.
#下面红色字体是添加的远程链接信息；其余代码是该文件原有的代码；
ORCL =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST =192.168.1.100)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = orcl)
)
)
<alias>= [ (DESCRIPTION_LIST = # Optional depending on whether u have
# one or moredescriptions
# If there isjust one description, unnecessary
]
(DESCRIPTION=
[ (SDU=2048) ] # Optional,defaults to 2048
# Can take values between 512 and 32K
[ (ADDRESS_LIST= # Optionaldepending on whether u have
# one or moreaddresses
# If there isjust one address, unnecessary ]
(ADDRESS=
[(COMMUNITY=<community_name>) ]
(PROTOCOL=tcp)
(HOST=<hostname>)
(PORT=<portnumber (1521 is astandard port used)>)
)
[ (ADDRESS=
(PROTOCOL=ipc)
(KEY=<ipckey (PNPKEY is astandard key used)>)
)
]
[ (ADDRESS=
[(COMMUNITY=<community_name>) ]
(PROTOCOL=decnet)
(NODE=<nodename>)
(OBJECT=<objectname>)
)
]
... # More addresses
[ ) ] # Optional depending on whether ADDRESS_LIST is used or not
[ (CONNECT_DATA=
(SID=<oracle_sid>)
[(GLOBAL_NAME=<global_database_name>) ]
)
]
[ (SOURCE_ROUTE=yes) ]
)
(DESCRIPTION=
[ (SDU=2048) ] # Optional,defaults to 2048
# Can takevalues between 512 and 32K
[ (ADDRESS_LIST= ] # Optionaldepending on whether u have more
# than oneaddress or not
# If there is justone address, unnecessary
(ADDRESS
[(COMMUNITY=<community_name>) ]
(PROTOCOL=tcp)
(HOST=<hostname>)
(PORT=<portnumber (1521 is astandard port used)>)
)
[ (ADDRESS=
(PROTOCOL=ipc)
(KEY=<ipckey (PNPKEY is astandard key used)>)
)
]
... # More addresses
[ ) ] # Optionaldepending on whether ADDRESS_LIST
# is being used
[ (CONNECT_DATA=
(SID=<oracle_sid>)
[(GLOBAL_NAME=<global_database_name>) ]
)
]
[ (SOURCE_ROUTE=yes) ]
)
[ (CONNECT_DATA=
(SID=<oracle_sid>)
[(GLOBAL_NAME=<global_database_name>) ]
)
]
... # More descriptions
[ ) ] # Optional depending onwhether DESCRIPTION_LIST is used or not
然后尝试链接
[oracle@localhost admin]$ sqlplusscott/tiger@orcl
SQL*Plus: Release 11.2.0.1.0 Production onSun Jul 28 13:59:59 2013
Copyright (c) 1982, 2009, Oracle. All rights reserved.
ERROR:
ORA-12541: TNS:nolistener
提示没有监听，这个时候查看远程数据库，监听已经启动；于是就把链接信息里的HOST信息又远程主机IP改为了主机名（由HOST = 192.168.1.100改为
HOST = 4728tef987uid34）
[oracle@localhost admin]$ sqlplusscott/tiger@orcl
SQL*Plus: Release 11.2.0.1.0 Production onSun Jul 28 14:02:38 2013
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise EditionRelease 10.2.0.3.0 - Production
With the Partitioning, OLAP and Data Miningoptions
Ok 链接成功；
另外用下面的方法也可以在没有配置tnsname.ora的情况下访问；
[oracle@localhost ~]$ sqlplus scott/tiger@//192.168.1.100/orcl
SQL*Plus: Release 11.2.0.1.0 Production onSun Jul 28 13:45:43 2013
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise EditionRelease 10.2.0.3.0 - Production
With the Partitioning, OLAP and Data Miningoptions
[oracle@localhost ~]$ sqlplus scott/tiger@//192.168.1.100/orcl
SQL*Plus: Release 11.2.0.1.0 Production onSun Jul 28 13:45:43 2013
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise EditionRelease 10.2.0.3.0 - Production
With the Partitioning, OLAP and Data Miningoptions