Re: how to get back value stored through get_hash_value function..

Saurabh Sharma wrote:
>
> hi list,
>
> dbms_utility.get_hash_value converts a string into its hash value..
> how do we get back the original value while selecting the entire
> record.
>
> TIA
>
> Saurabh Sharma
>
> saurabh00pc_at_yahoo.com
> http://www.geocities.com/saurabh00pc/stride.html

You can't. A hash function takes some input and transmogrifies it into something which hopefully is uniformly spread among a given spectrum. If h(a) is different from h(b) then a and b are different, but a != b doesn't imply h(a) != h(b) (if I remember well it means that the function is not injective. Too many years away and my daughters are too young for my having refreshed all this ...), which is why you *may* have collisions and when searching you must still compare against the non-hashed value. It's a bit like encryption, there is no reverse function.

--
Regards,

  Stephane Faroult
  Oriole Corporation
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Author: Stephane Faroult
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