Re: How to hash a set of columns ?

madhu17_at_vsnl.net (S Madhusudhanan) wrote in message news:<2eead8c7.0305070825.70f20add_at_posting.google.com>...
> Hi Gurus,
>
> I'm trying to develop a method to hash a set of columns and store the
> result in another column.
>
> Any query's on the set of columns would be hashed and the result would
> be looked up in the Hash Value column.
>
> Could somebody point me in the right direction on how to achieve this?
>
> Thanks and Regards
> S Madhusudhanan

You can get your own hash function or you can use the one from ORACLE. Like:

SQL> select dbms_utility.get_hash_value('abcd',100,800) from dual;

DBMS_UTILITY.GET_HASH_VALUE('ABCD',100,800)

                                        871

SQL> select 1 from dual where
871=dbms_utility.get_hash_value('abcd',100,800);

         1

         1

SQL> SQL> select * from test2;

C1 C2
-- ----------

b           2
c           3
e           1
K           6
P           0
G           0
ap          9
G           1
G           1

9 rows selected.

SQL> select dbms_utility.get_hash_value(c1||to_char(c2),100,800) hashed_col from test2;

HASHED_COL

       812
       373
       283
       161
       804
       568
       718
       390
       390

9 rows selected.

SQL>

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