No, this definetly opens up race conditions and lots of rollbacks and
reprocessing.
Eg (in pseudocode).
id = execute("SELECT MAX(id) FROM tablename") + 1;
...
result = execute("INSERT INTO tablename VALUE(id, ....)");
if (!result) { rollback(); repeat(); }
----
Either that or it would cause the database performance to slow down
whilst it holds a that table. Better just to have another unique
identifier in my reckoning.
Regards,
Michael S. E. Kraus
Software Developer/Technical Support Specialist
Wild Technology Pty Ltd
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-----Original Message-----
From: Benno [mailto:[EMAIL PROTECTED]
Sent: Monday, 18 October 2004 1:09 PM
To: torquemada
Cc: Michael Kraus; [EMAIL PROTECTED]
Subject: Re: [SLUG] Maximum process ID
On Mon Oct 18, 2004 at 12:58:42 +1000, torquemada wrote:
>
>OID's, (object-ID's) are made exactly for this purpose.
>if your database vendor does not provide this feature, lobby for it.
>ie PostgreSQL supports OID's and they are pretty much guaranteed to be
>unique
Well, the better idea is to start a transaction, get the next id from a
seqeunce, and then use this as the UID. I'm not sure if MySQL has
sequences, but I'm *sure* that this is a problem that is solved in some
way in the MySQL.
Benno
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