BASIC COMPRESSION in 11g : dbms_compression.get_compression_ratio

Hi ,

To estimate compression ratio , what is the value to use for  comptype parameter in case of BASIC COMPRESSION.

set serveroutput on

declare

v_blkcnt_cmp     pls_integer;

v_blkcnt_uncmp   pls_integer;

v_row_cmp        pls_integer;

v_row_uncmp      pls_integer;

v_cmp_ratio      number;

v_comptype_str   varchar2(60);

begin

dbms_compression.get_compression_ratio(

scratchtbsname   => '&Tbs_name',     

ownname          => '&User_name',          

tabname          => NULL,     --'Table_name',  

partname         => '&Partition_name',           

comptype         => dbms_compression.COMP_FOR_OLTP ,    --comp_for_query_high,   

blkcnt_cmp       => v_blkcnt_cmp,   

blkcnt_uncmp     => v_blkcnt_uncmp, 

row_cmp          => v_row_cmp,   

row_uncmp        => v_row_uncmp,