Massive Update commit every 1000 records

• *
  *We need to shrink SSN to the last 4 digit.*
  
• *
  *update sales set ssn=to_number(substr(to_char(ssn),-4));*
  **
  *But the sales table is quite large and we want to commit every 1000
  records.*
• *
  *Does anyone have a better idea to do this rather than below?*
  
• *
  *Thanks,*
  
• *
  *Roger*
  

declare
  cursor c12 is select ssn from sales for update of ssn;   n number := 0;
begin

   for eachc12 in c12 loop
    if eachc12.ssn is not null then

      n := n + 1;
      update sales set ssn=to_number(substr(to_char(ssn),-4)) where current
of c12;
      if ( n = 1000 )
      then
         commit;
      end if;

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