Error
1、执行sqlplus sys/oracle@orcl

2、结果：
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified

3、listener.ora

LISTENER =  (DESCRIPTION_LIST =    (DESCRIPTION =      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.178)

(PORT = 1521))    )  )

4、sqlnet.ora

SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH=(TNSNAMES,HOSTNAME)

5、tnsnames.ora

orcl =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.178)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

[解决办法]
执行下:tnsping orcl，看看什么结果
[解决办法]
检查输入的服务名与配置的服务名是否一致
另外注意生成的本地服务名文件(Windows下如D:oracleora92networkadmin tnsnames.ora，Linux/Unix下/network/admin/tnsnames.ora)里每项服务的首 行服务名称前不能有空格。