问在删除前找到由序列生成的最后一个数字

EN

create or replace procedure pr_ddl_oper as
  v_oty          varchar2(75) := ora_dict_obj_type;
  v_don          varchar2(75) := ora_dict_obj_name;
  v_evt          varchar2(75) := ora_sysevent;
  v_olu          varchar2(75) := nvl(ora_login_user,'Unknown Schema');
  v_sql          ora_name_list_t;
  v_stm          clob;
  v_sct          owa.vc_arr;
  n              pls_integer;
  n_max          pls_integer := 10000; -- max number of rows for CLOB object 
                                       -- to hold object's source.
begin
      v_sct(1) := 'SESSIONID';
      v_sct(2) := 'IP_ADDRESS';
      v_sct(3) := 'TERMINAL';
      v_sct(4) := 'OS_USER';
      v_sct(5) := 'AUTHENTICATION_TYPE';
      v_sct(6) := 'CLIENT_INFO';
      v_sct(7) := 'MODULE';
      for i in 1..7
      loop
       v_sct(i) := sys_context('USERENV',v_sct(i));
      end loop;
      select decode(v_sct(1),0,null,v_sct(1)),decode(upper(v_sct(3)),
            'UNKNOWN',null,v_sct(3)) 
        into v_sct(1),v_sct(3) 
        from dual;

       n := ora_sql_txt( v_sql );
      if n > n_max then
       n := n_max;
      end if;
      for i in 1..n
      loop
       v_stm := v_stm || v_sql(i);
      end loop;

       insert into log_ddl_oper(event_time,usr,evnt,stmt,sessionid,ip,terminal,os_user,
         auth_type,object_type,object_name,client_info,module_info)
       values(sysdate,v_olu,v_evt,v_stm,v_sct(1),v_sct(2),v_sct(3),v_sct(4),v_sct(5),
         v_oty,v_don,v_sct(6),v_sct(7));
end;

--| Compiling this trigger, especially for Production Systems, should be handled with care |

create or replace trigger system.trg_admin_ddl before ddl on database
declare
begin
 pr_ddl_oper;
end;

select last_number
  from dba_sequences 
  as of timestamp to_timestamp('2018-11-27 23:50:17', 'YYYY-MM-DD HH24:MI:SS') s 
 where s.sequence_name = 'MYSEQ';

select l.event_time 
--> returns to_timestamp('2018-11-27 23:50:17', 'YYYY-MM-DD HH24:MI:SS')
--> to use for the above SQL Select statement
  from log_ddl_oper l
 where l.object_name = 'MYSEQ'
   and l.evnt = 'DROP'