ora-02085:的注解是：
database link name connects to name
cause: The database link attempted to connect to a database with a different name.
The name of the database link must be the same name as the name of the database.
Action: Create a database link with same name as the database to which it connects.
意思是:If u set the parameter 'global_names' to true,the db link name connected to this server must equal db_name + db_domain.
很多时候我们只是让dblink的名字等于了db_name,所以创建出错
