ORA-12514:TNS:监听程序当前无法识别连接描述符中请求的服务。

修改listener.ora，添加以下红色部分内容

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = E:\oracle\product\10.2.0\db_1)
      (PROGRAM = extproc)
    )
    (SID_DESC =
 (GLOBAL_DBNAME = orcl)
 (ORACLE_HOME = E:\oracle\product\10.2.0\db_1)
 (SID_NAME = orcl)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    )
  )