Centos5.5 安装Oracle11g客户端，配置了本地的net服务后，用sqlplus连接报错：
tnsnames.ora配置如下
orcl = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.39.199)(PORT = 1521)) (CONNECT_DATA = (SERVICE = DEDICATED) (SERVICE_NAME = orcl) ) )
解决方案：修改tnsname.ora文件内容如下：
172.16.39.199 = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.39.199)(PORT = 1521)) (CONNECT_DATA = (SERVICE = DEDICATED) (SERVICE_NAME = orcl) ) )
再次连接，成功。
ORA-12504: TNS:listener was not given the SERVICE_NAME in CONNECT_DATA
原文：http://www.cnblogs.com/Rainbow-G/p/4234434.html