Parsing which columns used in a query

Question

Hi,
i try to write my own advisor :-) I´m looking for a package that can help me to find out which columns a used in query in a codition
Example:
select 1 from emp
where deptno=10
and job='CLERK';
=> deptno and clerk
I worked with col_usage$, but it seems not always correct, and it´s not updated when you zuse explain plan ...
Does anybody know, how Oracle´s dbms_advisor/dbms_sqltune finds out which columns are used in a condition ?
Thanks
Marco

Answer 1

mpatzwahl wrote:
i try to write my own advisor :-)Oh dear, that is completely insane. Why not use the one provided?
You would need to write a SQL parser.
The language definition is here
http://docs.oracle.com/cd/E11882_01/server.112/e26088/toc.htm
And don't forget that a function could be used in the condition so you will need to parse PL/SQL also
http://docs.oracle.com/cd/E11882_01/appdev.112/e25519/toc.htm
Try it out on something simple like this and see how far you get
{message:id=1908539}
SQL> create or replace function f1 return varchar2 as
  2  l_dummy dual.dummy%type;
  3  begin
  4    select dummy into l_dummy from dual;
  5    return l_dummy;
  6  end;
  7  /
Function created.
SQL> edi
Wrote file afiedt.sql
  1  create or replace function f2 return varchar2 as
  2  begin
  3    return 'X';
  4* end;
SQL> /
Function created.
SQL> create or replace view v as
  2  select
  3      dummy a,
  4      (select dummy from dual) b,
  5      f1 c,
  6      f2 d,
  7      'X' e
  8  from dual;
View created.
SQL> select * from v where c = 'X';
A B C D E
X X X X X