出现数据库的连接问题可在命令行下使用 tnsping 服务名 来检查出错原因。

常见错误有：

ORA-12535: TNS: 操作超时

首先关闭防火墙，这是最常见的连接出错原因。

如果仍然不行，检查 tnsnames.ora 文件配置，主要是主机名称是否正确

# TNSNAMES.ORA Network Configuration File: E:\oracle\ora92\network\admin\tnsnames.ora

# Generated by Oracle configuration tools.

ORCL.DBSE.LAMOST =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.1)(PORT = 1521))

)

(CONNECT_DATA =

(SID = orcl)

(SERVER = DEDICATED)

)

)

ORCL =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.1)(PORT = 1521))

)

(CONNECT_DATA =

(SERVICE_NAME = orcl.dbse.lamost)

)

)

ORA-12541: TNS: 没有监听器

在命令行下执行 lsnrctl start 启动监听器。