From: | David Garamond <lists(at)zara(dot)6(dot)isreserved(dot)com> |
---|---|
To: | "D(dot) Dante Lorenso" <dante(at)lorenso(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Drawbacks of using BYTEA for PK? |
Date: | 2004-01-12 13:42:36 |
Message-ID: | 4002A44C.1070004@zara.6.isreserved.com |
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Thread: | |
Lists: | pgsql-general |
D. Dante Lorenso wrote:
> GUID? Isn't that really nothing more than an MD5 on a sequence?
>
> SELECT (MD5(NEXTVAL('my_table_seq'))) AS my_guid;
I know there are several algorithms to generate GUID, but this is
certainly inadequate :-) You need to make sure that the generated GUID
will be unique throughout cyberspace (or to be more precise, the GUID
should have a very very small chance of colliding with other people's
GUID). Even OID is not a good seed at all.
Perhaps I can make a GUID by MD5( two random numbers || a timestamp || a
unique seed like MD5 of '/sbin/ifconfig' output)...
> Since 7.4 has the md5 function built-in, there's your support ;-)
Well, until there's a GUID or INT128 or BIGBIGINT builtin type I doubt
many people will regard PostgreSQL as fully supporting GUID. I believe
there's the pguuid project in GBorg site that does something like this.
--
dave
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