Re: Generating random unique alphanumeric IDs

From: "Daniel Verite" <daniel(at)manitou-mail(dot)org>
To: "Thom Brown" <thombrown(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Generating random unique alphanumeric IDs
Date: 2009-08-21 12:04:29
Message-ID: 36bae15f-7b98-4ead-8b5f-2c67f73137fc@mm
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Thom Brown wrote:

> If this results in an unpredictable and non-duplicating loop of generated
> sets of characters, that would be ideal. Would a parallel for this be a
> 5-character code possibly transcoded from a 6-character GUID/UUID? (a-h +
> j+n + p-z + A-H + J-N + P+Z + 2-9 = 56 possible characters, 56^5 =
> 550,731,776, 550,731,776 / 16 (hex character set) ^ 6 (characters) = just
> over 32.), so wouldn't actually use up all possible combinations. :/

56^5 is the number of strings that you can form with 5 letters of the 56
letters alphabet. But independantly of that , what is the minimum number of
different values that you truly need?

Best regards,
--
Daniel
PostgreSQL-powered mail user agent and storage: http://www.manitou-mail.org

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