Identifying Sql Statements that Could use Bind Parameters

This function will identify statements that are the same if they used bind variables:

create or replace function remove_constants( p_query in varchar2 )
return varchar2
as l_query long;

l_char varchar2(1);
l_in_quotes boolean default FALSE;

BEGIN
for i in 1 .. length( p_query )
loop l_char := substr(p_query,i,1);
if ( l_char = '''' and l_in_quotes ) then l_in_quotes := FALSE;
elsif ( l_char = '''' and NOT l_in_quotes ) then l_in_quotes := TRUE;
l_query := l_query '''#';
end if;

if ( NOT l_in_quotes ) then
l_query := l_query l_char;
end if;
end loop;

l_query := translate( l_query, '0123456789', '@@@@@@@@@@' );

for i in 0 .. 8 loop
l_query := replace( l_query, lpad('@',10-i,'@'), '@' );
l_query := replace( l_query, lpad(' ',10-i,' '), ' ' );
end loop;
return upper(l_query);
END;

Now following this example can show how the above function can be used:

create global temporary table sql_area_tmp
on commit preserve rows
as
select sql_text,sql_text sql_text_two_constants
from v$sqlarea
where 1=0


This is an sql example that does not use bind parameters and so essentially the same statement is read and parsed repeatedly:

DECLARE

cursor c1 is
select object_name
from dba_objects;

l_object dba_objects.object_name%type;

BEGIN

for c1rec in c1 loop
execute immediate 'insert into pn_temp values('''''c1rec.object_name''''')';
end loop;

END;;

Scripts below will show how this statement can be identified as an Sql statement that should be re-examined for re-writing with bind parameters:

insert into sql_area_tmp(sql_text)
select sql_text
from v$sqlarea

update sql_area_tmp
set sql_text_two_constants = remove_constants(sql_text)

select sql_text_two_constants,count(*)
from sql_area_tmp
group by sql_text_two_constants
order by 2 desc

Sql statemnets that should be re-examined will appear at the top with a high count.