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

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The add-must-be-new precondition only applies if DAV:add is specified in=20
the LABEL request (i.e. you want it to fail if the label is already=20
applied to some version).

You use DAV:set in the LABEL request if you want to move the label from=20
one version to another.

Cheers,
Geoff

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

>=20
> Hi,
>=20
> 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.
>=20
> 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.
>=20
> Regards,
>=20
> Werner.
> --=20
> Werner Donn=E9  --  Re
> Engelbeekstraat 8
> B-3300 Tienen
> tel: (+32) 486 425803   e-mail: [email protected]
>=20

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<br><font size=3D2 face=3D"sans-serif">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).</font>
<br>
<br><font size=3D2 face=3D"sans-serif">You use DAV:set in the LABEL request
if you want to move the label from one version to another.</font>
<br><font size=3D2 face=3D"sans-serif"><br>
Cheers,<br>
Geoff</font>
<br>
<br><tt><font size=3D2>Werner wrote on 07/14/2006 12:58:41 PM:<br>
<br>
&gt; <br>
&gt; Hi,<br>
&gt; <br>
&gt; The add-must-be-new precondition of the LABEL method makes it<br>
&gt; impossible to move a label. Moving a label requires a remove<br>
&gt; followed by an add, which are two round-trips. Instead of<br>
&gt; having the precondition, the postcondition label-must-be-unique<br>
&gt; would provide the same data integrity, while avoiding the<br>
&gt; extra round-trip.<br>
&gt; <br>
&gt; An additional advantage is that the move would be atomic. A<br>
&gt; remove followed by an add is not. The impact of a failure in<br>
&gt; between can be dramatic.<br>
&gt; <br>
&gt; Regards,<br>
&gt; <br>
&gt; Werner.<br>
&gt; -- <br>
&gt; Werner Donn=E9 &nbsp;-- &nbsp;Re<br>
&gt; Engelbeekstraat 8<br>
&gt; B-3300 Tienen<br>
&gt; tel: (+32) 486 425803 &nbsp; e-mail: [email protected]<br>
&gt; <br>
</font></tt>
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