Is it possible to re-initialize sequence

This thread over on Stack Overflow has the information you are looking for. There are two main options:

1. Drop the sequence and re-create it, or

2. Use a trick, courtesy of Tom Kyte:

   either as a one-off:

   alter sequence seq increment by {minus_the_current_value} minvalue 0;
   

   or you can create a procedure if you need to do this regularly:

   create or replace
   procedure reset_seq( p_seq_name in varchar2 )
   is
       l_val number;
   begin
       execute immediate
       'select ' || p_seq_name || '.nextval from dual' INTO l_val;
   
       execute immediate
       'alter sequence ' || p_seq_name || ' increment by -' || l_val || 
                                                         ' minvalue 0';
   
       execute immediate
       'select ' || p_seq_name || '.nextval from dual' INTO l_val;
   
       execute immediate
       'alter sequence ' || p_seq_name || ' increment by 1 minvalue 0';
   end;
   /