create public  database link MyLinkTest; 
　　connect to 账号 identified by 密码 
　　using 'DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 服务器地址)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = ORCL)
    )' 
    
    -- DESCRIPTION 也可以替换成 tnsnames.ora 中的节点值

--select owner,object_name from dba_objects where object_type='DATABASE LINK';

--drop public database link MyLinkTest;; 

MERGE INTO T_CONTENT t

USING T_CONTENT@MyLinkTest  s

ON ( t.id = s.id )   

WHEN MATCHED THEN UPDATE SET t.CONTENT = s.CONTENT