通过trigger防止指定用户drop

sqlplus /nolog

conn /as sysdba;

SQL> create or replace trigger no_droping_for_you before
  2  drop on database
  3  begin
  4  if(user='ZHANGBIN') then
  5  raise_application_error( -20001, 'No dropping allowed');
  6  end if;
  7  end;
  8  /

Trigger created.

SQL> connect zhangbin
Enter password:
Connected.
SQL> drop table t;
drop table t
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20001: No dropping allowed
ORA-06512: at line 3