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RE: Hashing

Peter Trast — Tue, 07 Feb 2012 08:31:06 GMT

OK, every other QotD has had explanations that were easy (for me) to understand. Since the question asked about the "relationship" between the 2, I assumed none since they were different variables.Answer C, deterministic and always the same, looked right and I was inclined to pick that since I knew that was true, but what does that have to do with the relationship between the two? Or am I just totally misreading the question?

RE: Hashing

Iulian -207023 — Wed, 25 Jan 2012 06:59:06 GMT

Thank you for the questionIulian

RE: Hashing

codebyo — Tue, 24 Jan 2012 15:00:50 GMT

I've never used the HashBytes() function so I learnt something new.I got it right at first because of logic thinking but the options had me wondering and I had to research a little before answering.Thank you for this QoTD.

RE: Hashing

Paul White — Tue, 24 Jan 2012 12:24:43 GMT

Good question.[code="sql"]CREATE FUNCTION dbo.Hash_SHA (@data nvarchar(200))RETURNS TABLE WITH SCHEMABINDING AS RETURNSELECT HASHBYTES('SHA', @data) AS hash_valueGO-- Returns 1 (true)SELECT OBJECTPROPERTYEX(OBJECT_ID(N'dbo.Hash_SHA', N'IF'), 'IsDeterministic');[/code]

RE: Hashing

Revenant — Tue, 24 Jan 2012 09:26:39 GMT

An easy one - thanks, Steve!

RE: Hashing

BarbW — Tue, 24 Jan 2012 09:14:57 GMT

Nice question, thanks for the points!

RE: Hashing

L' Eomot Inversé — Tue, 24 Jan 2012 09:09:01 GMT

[quote][b]paul.knibbs (1/24/2012)[/b][hr]A non-deterministic hash function wouldn't be terribly useful, would it? ;-)[/quote]Why not? I can think of at least one use for one. In the old days the apprentice engineer was sent to fetch a bucketful of holes, more recently people were asked to design a device driver for the GSD, and today we could assign the task of producing an effective access control system using an indeterminate hash - the [strike]victim[/strike]trainee would have exactly the same chance of carrying out this task as anyone did with the traditional spoof tasks.

RE: Hashing

Steve Jones - SSC Editor — Tue, 24 Jan 2012 09:00:42 GMT

Glad you liked the question. I was working on something else and learned a few things here.

RE: Hashing

mtassin — Tue, 24 Jan 2012 08:41:21 GMT

[quote][b]paul.knibbs (1/24/2012)[/b][hr]A non-deterministic hash function wouldn't be terribly useful, would it? ;-)[/quote]That's what I was thinking... I had to harken back to Advanced Concepts in C... at least it was considered advanced concepts in C 14 years ago.... these days this is probably beginners stuff (Hashes and the like)....Aaah age.... where'd I put my walker?

RE: Hashing

SQLRNNR — Tue, 24 Jan 2012 08:39:39 GMT

Thanks yet again Steve.

RE: Hashing

Dave62 — Tue, 24 Jan 2012 08:29:55 GMT

[quote][b]Mattrick (1/24/2012)[/b][hr] ... that shows why salting your hashes is so important ... [/quote]A little bit of pepper doesn't hurt either. :hehe:

RE: Hashing

Mattrick — Tue, 24 Jan 2012 08:20:27 GMT

Great question that shows why salting your hashes is so important.Thanks,Matt

RE: Hashing

paul.knibbs — Tue, 24 Jan 2012 07:00:57 GMT

A non-deterministic hash function wouldn't be terribly useful, would it? ;-)

RE: Hashing

Ryan Barrett — Tue, 24 Jan 2012 06:00:26 GMT

Nice question. I had never heard of HashBytes before.

RE: Hashing

cengland0 — Tue, 24 Jan 2012 05:53:51 GMT

[quote][b]Britt Cluff (1/24/2012)[/b][hr]Yeah, I got my point. Thanks for the question Steve.[/quote]Two points for today.

RE: Hashing

Britt Cluff — Tue, 24 Jan 2012 05:47:44 GMT

Yeah, I got my point. Thanks for the question Steve.

RE: Hashing

Thomas Abraham — Tue, 24 Jan 2012 05:37:19 GMT

An unexpected adventure into hashing - Hash Tuesday anyone?Thanks for the stimulating question Steve.

RE: Hashing

Koen Verbeeck — Tue, 24 Jan 2012 04:00:19 GMT

Nice question, but quite easy as hash functions are deterministic by design.

RE: Hashing

rfr.ferrari — Tue, 24 Jan 2012 03:27:46 GMT

This issue is so obvious that i was confused!!!Good question!thanks Steve!!!!

RE: Hashing

Toreador — Tue, 24 Jan 2012 02:59:24 GMT

Nice question, but the documentation linked to doesn't really explain anything!

RE: Hashing

Michael Lysons — Tue, 24 Jan 2012 02:33:23 GMT

Great question as it taught me about Hashbytes, which is something I did not know about.

RE: Hashing

cengland0 — Tue, 24 Jan 2012 02:30:41 GMT

This was so easy I answered right away without hesitation. Then, I noticed it was a two point question and that gave me doubt. Those two point questions always have some twist to them. So, I looked up the definition of deterministic to make sure I understood the word correctly.Definition: [i]In computer science, a deterministic algorithm is an algorithm which, in informal terms, behaves predictably.[/i]Also, for those interested, Steve had a nice post about this function on June 28, 2011:[url]http://www.sqlservercentral.com/blogs/steve_jones/2011/06/28/hashbytes-_1320_-a-t_2D00_sql-function/[/url]I got it right but I was scared to push that submit button.

RE: Hashing

paul s-306273 — Tue, 24 Jan 2012 01:51:04 GMT

Easy question - if you know the answer.(I had to look!)

RE: Hashing

Carlo Romagnano — Tue, 24 Jan 2012 01:38:20 GMT

It seems too easy. So, I digged in deep on google and MSDN.Thanks for the qotd. :-D

RE: Hashing

bitbucket-25253 — Mon, 23 Jan 2012 20:53:29 GMT

Nice question really had to dig deep into my memory to, well answer the question.

Hashing

Steve Jones - SSC Editor — Mon, 23 Jan 2012 20:52:11 GMT

Comments posted to this topic are about the item [B]Hashing[/B]