-- Create sequence 
create sequence SEQ_PUSH
minvalue 1
maxvalue 9999999999
start with 1
increment by 1
cache 20;

create or replace trigger tr_id_insert
  before insert on t_push  
  for each row
declare
  -- local variables here
begin
  select seq_user_id.nextval into :new.id from dual;
end tr_id_insert;