potential changes to VODataService!

[KevinBenson]

Hi Ray I cannot answer for Guy, but yes a Registry for Astrogrid does 
keep local copies of the schema for validation, if there is no local 
copy as long as there is a xsi:schemaLocation defined for any 
new/extended schema then it will validate and store into the database. 

So if a Registry has an older/today 1.0 schema and a component/client 
writes XML to the new 1.0 schema filling in the optional elements then 
it would be rejected because it would check the local copy.

Again I am not to concerned since 1.0 is still quite new and nobody is 
really adopting it just yet and there is a good chance our registries 
will need another upgrade so we could pick up the new schema if it gets 
updated soon.

cheers,
Kevin


Ray Plante wrote:
> Hi Guy and Kevin,
>
> Thanks for your comments.  Since you are among the few that have 
> responded, they carry a lot of weight.
>
> I want probe your situations a bit more.  Below, I refer to your 
> application.  For Guy, I'm refering to the software you mentioned.  
> For Kevin, I mean your registries.  Keep in mind that the changes 
> being proposed are such that existing instance documents will still be 
> valid.
>
> 1.  Does your application do validation?
> 2.  Do you keep and use a copy of the schema local to your application or
>     does your application download it transparently from www.ivoa.net?
> 3.  Do you use an XML-binding tool such as JAXB?
> 4.  Do you tolerate VOResource records that invoke extensions that were
>     previously unknown to you?
> 5.  If an incoming VOResource record contained elements from a known
>     schema that you were not expecting (i.e. it looks invalid to you),
>     would your application break?    (This might occur, for example, if
>     you are using JAXB or rely on elements appearing in a particular
>     order).
> 6.  Can your application be upgraded simply by retrieving the latest
>     version of the schema, or is there more involved?
>
> On Thu, 7 Jun 2007, KevinBenson wrote:
>> Also note I am thinking this might break one of your rules you 
>> mentioned on Nov 21 'Version Numbers on XMLSchemata' see this url: 
>> http://www.ivoa.net/forum/registry/0611/1760.htm
>
> I assume that you are refering to rule #2.
>
>   2.  backward compatible changes that should not invalidate/break
>       existing instances or applications
>
> These would not invalidate existing instances.  My questions above are 
> about examining the effect on your applications.
>
> Not updating the namespace represent a low-to-middle ground of 
> disruption. When you change the namespace, either everyone is highly 
> disrupted upgrading their records and applications or no one is 
> disrupted, because the change is not adopted.  If you don't change the 
> namespace and the syntax is backward-compatible to the instance 
> documents, then only some subset of applications are affected.
>
> thanks!
> Ray
>