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Hello kc,
How do I get off the email list?
Anthony
----- Original Message ----- 
From: "Karen Coyle" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, March 13, 2009 4:53 PM
Subject: Re: [MODS] URL for the current version of mods


> Andrew, it sounds like you are saying that there shouldn't be a generic 
> URL... ? I believe that people asked for it in the past, but maybe it's 
> not a good idea. It seems to work when updates are backward compatible but 
> not when they aren't.
>
> kc
>
> Houghton,Andrew wrote:
>>> From: Metadata Object Description Schema List [mailto:[log in to unmask]] On
>>> Behalf Of Rick Beaubien
>>> Sent: Thursday, March 12, 2009 5:02 PM
>>> To: [log in to unmask]
>>> Subject: [MODS] URL for the current version of mods
>>>
>>> The current version of MODS is available both through a version
>>> specific
>>> URL (http://www.loc.gov/standards/mods/v3/mods-3-3.xsd) as well as a
>>> more generic URL (http://www.loc.gov/standards/mods/mods.xsd).  Can
>>> users count on the more generic URL always pointing to the most recent
>>> version of the MODS schema that is backwards compatible through version
>>> 3.1?  (I believe that there is a break in compatibility between version
>>> 3.0 and 3.1).  Or, to phrase the question a little differently, if a
>>> new
>>> version of the MODS schema was produced that was not backwards
>>> compatible with versions 3.1-3.3, would it replace the 3.3 schema that
>>> is now available via the generic URL
>>> http://www.loc.gov/standards/mods/mods.xsd?  I am asking this because
>>> of
>>> its implications for how the schemaLocation in mods instances should be
>>> set up.
>>>
>>
>> What goes in xsi:schemaLocation is the namespace URI and a URI to the XML
>> schema for MODS.  The namespace URI must match the targetNamespace 
>> attribute
>> in the XML schema for MODS which currently is:
>>
>>   targetNamespace="http://www.loc.gov/mods/v3"
>> for the XML schema URI you should be using the version specific URI in 
>> the
>> xsi:schemaLocation attribute of your XML instance document.  Otherwise, 
>> as
>> your question suggests when version 4 of the MODS specification comes out
>> and it is not backward compatible, LC will have to change the target
>> namespace URI to something like:
>>
>>   targetNamespace="http://www.loc.gov/mods/v4"
>> anybody still using version 3 of MODS and who mistakenly used the generic 
>> URI in their xsi:schemaLocation attribute of their XML instance documents 
>> will now have a problem since the targetNamespace in the XML schema 
>> returned from the generic URI will not match the namespace URI they used 
>> in the xsi:schemaLocation attribute specified in their XML instance 
>> documents.  If
>> the XML instance document is being read by an XML parser that is schema
>> aware, then the XML parser will throw an error, otherwise the application 
>> processing the MODS instance document will not know there is a problem. 
>> The generic XML schema URI should never be used in xsi:schemaLocation.
>>
>> Unfortunately, the LC web site doesn't make it clear which one you should 
>> be
>> using and when you dereference the generic URI you get back an HTTP 200 
>> OK
>> status with the HTTP entity containing the latest version of the MODS 
>> schema.
>> What I believe the LC web site should be doing when dereferencing the 
>> generic URI is to respond back with an HTTP 302 Found status and an HTTP 
>> Location
>> header containing the URI to the latest version of the MODS schema.  Then 
>> it
>> would be obvious that you should be using the version specific URI 
>> instead
>> of the generic URI.
>>
>>
>> Andy.
>>
>>
>>
>
> -- 
> -----------------------------------
> Karen Coyle / Digital Library Consultant
> [log in to unmask] http://www.kcoyle.net
> ph.: 510-540-7596   skype: kcoylenet
> fx.: 510-848-3913
> mo.: 510-435-8234
> ------------------------------------