tnsnames.ora ：该文件一般存放于{ORACLE_HOME}\NETWORK\ADMIN 目录下，pl\sql会加载该链接配置文件。
在plsql中，使用帮助->支持信息->TNS File的位置信息就是tnsnames.ora文件的位置。
# tnsnames.ora Network Configuration File: E:\app\Administrator\product\11.2.0\dbhome_1\NETWORK\ADMIN\tnsnames.ora # Generated by Oracle configuration tools. LISTENER_ORCL = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521)) ORACLR_CONNECTION_DATA = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521)) ) (CONNECT_DATA = (SID = CLRExtProc) (PRESENTATION = RO) ) ) ORCL = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521)) ) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl) ) ) someSID = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.0.0.9)(PORT = 1521)) ) (CONNECT_DATA = (SID = somesid) ) ) CONNECT_DATA: 该数据有SID、SERVICE_NAME之分，需要注意对待。ORCL：该配置是配置的本地Oracle数据库，配置的服务名字：orclsomeSID：该配置是配置的远程Oracle数据库，配置的服务ID：somesidHOST：主机ID或者域名PORT：主机端口PROTOCOL：使用协议
plsql工具和Oracle客户端下载（含安装说明）：
https://download.csdn.net/download/bof_jangle/10695929
