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Re: Precondition add-must-be-new-label

From: Geoffrey M Clemm <geoffrey.clemm@us.ibm.com>
Date: Sat, 15 Jul 2006 11:47:42 -0400
To: werner.donne@re.be
Cc: ietf-dav-versioning@w3.org, ietf-dav-versioning-request@w3.org
Message-ID: <OFEE6F5F8F.1991B300-ON852571AC.00568509-852571AC.0056C399@us.ibm.com>
The add-must-be-new precondition only applies if DAV:add is specified in 
the LABEL request (i.e. you want it to fail if the label is already 
applied to some version).

You use DAV:set in the LABEL request if you want to move the label from 
one version to another.

Cheers,
Geoff

Werner wrote on 07/14/2006 12:58:41 PM:

> 
> Hi,
> 
> The add-must-be-new precondition of the LABEL method makes it
> impossible to move a label. Moving a label requires a remove
> followed by an add, which are two round-trips. Instead of
> having the precondition, the postcondition label-must-be-unique
> would provide the same data integrity, while avoiding the
> extra round-trip.
> 
> An additional advantage is that the move would be atomic. A
> remove followed by an add is not. The impact of a failure in
> between can be dramatic.
> 
> Regards,
> 
> Werner.
> -- 
> Werner Donné  --  Re
> Engelbeekstraat 8
> B-3300 Tienen
> tel: (+32) 486 425803   e-mail: werner.donne@re.be
> 
Received on Saturday, 15 July 2006 15:47:58 GMT

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