通过Navicat Premium 12远程登入Oracle

#进入oracle

su - oracle

#打开监听服务

lsnrctl start

#进入oracle数据库

sqlplus / as sysdba
或者
sqlplus 用户名/密码

startup

#查看实例名

select instance_name from v$instance;

#查看服务名

select global_name from global_name;
或
show parameter names

测试一下是否能外部链接oracle成功

报错no matching authentication protocol

vi /usr/local/products/oracle12c/network/admin/sqlnet.ora
#添加如下内容

SQLNET.ALLOWED_LOGON_VERSION=8

链接报错 listener does currently know of server requested in connect descriptor

 vi /usr/local/products/oracle12c/network/admin/samples/tnsnames.ora

#添加如下内容，修改对应数据库服务名和本机IP地址


3.10 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.3.10)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = CDB1)
    )
  )

忘了用户密码，修改用户密码 
alter user system identified by 123456;