在自己的Oracle安装目录找到以下文件：tnsnames.ora
例如：
D:\app\Administrator\product\11.1.0\db_1\NETWORK\ADMIN\tnsnames.ora
打开文件添加以下内容：
非集群，数据库在一台服务器上：
名称 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip地址)(PORT = 端口号))
)
(CONNECT_DATA =
(SERVICE_NAME = 数据库实例)
)
)
//例如下面这个
KZJN =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.162.146)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = orcl)
)
)
集群，数据库在多台服务器上：
名称 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip地址1)(PORT = 对应端口号))
(ADDRESS = (PROTOCOL = TCP)(HOST = ip地址1)(PORT = 对应端口号))
(LOAD_BALANCE = yes)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SID = 数据库实例)
)
)
//例如下面这个
JQ =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.190.88)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.190.99)(PORT = 1521))
(LOAD_BALANCE = yes)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SID = tmis21)
)
)
保存修改后打开plsql，在数据库下拉列表中回多出新添加的内容，选择对应的下拉项，填写用户名密码即可。
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