环境介绍：
本人在winxp环境下配置成功，下面是其他人的配置情况。
服务器 Windows 7旗舰版 + Oracle 11g R2
客户机 Windows 7专业版 + PL/SQL Developer 7 + instantclient-basic-win32-11.2.0.1.0.zip（去oracle官网下载即可）
配置服务器：
找到目录“…/app/Administrator/product/11.2.0/dbhome_1/NETWORK/ADMIN”下面的listener.ora、tnsnames.ora两个文件。
修改listener.ora文件：
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = CLRExtProc)
(ORACLE_HOME = D:/app/Administrator/product/11.2.0/dbhome_1)
(PROGRAM = extproc)
(ENVS = "EXTPROC_DLLS=ONLY:D:/app/Administrator/product/11.2.0/dbhome_1/bin/oraclr11.dll")
)
(SID_DESC =
(GLOBAL_DBNAME = [全局数据库名称])
(ORACLE_HOME = D:/app/Administrator/product/11.2.0/dbhome_1)
(SID_NAME = [实例名称])
)
)
......
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = [服务器的IP地址])(PORT = 1521))
)
)
修改tnsnames.ora：
LOCALORCL =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = [服务器的IP地址])(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SID = localorcl)
)
)
黄色标注的为添加部分，“localorcl”是我自己的数据库名称，按照自己的设置。
配置客户机：
Oracle轻量级客户端：
把instantclient-basic-win32-11.2.0.1.0.zip解压缩在“D:/ instantclient”中，在“D:/ instantclient”目录下面创建“network”文件夹，在“network”下面创建“admin”文件夹，在“admin”下面创建文件“tnsnames.ora”，“tnsnames.ora”文件内容为：
[实例名] =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = [数据库主机IP地址])(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = [服务名])
)
)
PL/SQL Developer：
打开PL/SQL Developer，Tools -> Preferences -> Oracle -> Connection
设置Oracle Home为“D:/ instantclient”和OCI Library为“D:/ instantclient/oci.dll”
然后重新启动PL/SQL Developer，在登录界面的“Database”中就会看到刚才设置好的数据库连接，输入有效的用户名和密码就可以登录了。
