Variable-like object in OWB

Question

Hi all,
I am creating a mapping from which I want to use the values contained in an external file, which looks like follows:
2701
2702
2703
2704
I need to compare a field from each record introduced in the mapping and see if it starts with any of the values stated in the external file mentioned above.
What I did was loading the file in a staging table, and creating a function in which, for every record in the mapping I try to match one of its fields with any of the values in the external file, using a cursor. The problem is, input files have around 50 million subscribers, and with this solution I am fetching the values in the external file 50 million times, and overall performance is hugely affected.
Is there any way of storing those values stated above in a variable/array/something in order to not to use a cursor to query the database as many times as records the input files have?
Thanks in advance
G.
Edited by: [email protected] on Nov 4, 2009 3:28 PM

Answer 1

No, the values can vary but there is a maximum of 11 characters.I think the fastest way is to autogenerate "lookup" function before each mapping run,
the source code of this function should be like
create or replace function func_lookup(P_FIELD IN VARCHAR2) return VARCHAR2 is
begin
  if P_FIELD like '2701%' then return '2701';
  elsif P_FIELD like '2702%' then return '2702';
  elsif P_FIELD like '2703%' then return '2703';
  // code for rest rows from from external table
  end if;
  return NULL;
end;For generating "lookup" function you can use other stored PL/SQL procedure, for example
create or replace function proc_gen_lookup is
  v_source_code VARCHAR2(32000);
begin
  v_source_code := 'create or replace function func_lookup(P_FIELD IN VARCHAR2) return VARCHAR2 is begin ';
  for exttab_rec in (select code from your_extrnal_table order by length(code) desc) LOOP
      // ADD correct code for first iteration - genrate IF instead ELSIF
      v_source_code := v_source_code || ' elsif P_FIELD like '''||exttab_rec.code||'%'' then return '''||exttab_rec.code||'''; ';
  END LOOP;
  v_source_code := v_source_code || ' end if; return NULL; end;';
  EXECUTE IMMEDIATE v_source_code;
end;How many rows in your external table (large number of rows can produce VERY large code for "lookup" procedure which doesn't fit into PL/SQL varchar2 variable)?
Or you can try rewrite your function (with cursor) to select from index organised table (instead of external table).
Regards,
Oleg