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Author Topic: Dataflow Constrained?  (Read 709 times)

JamesGardner

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Dataflow Constrained?
« on: November 10, 2011, 12:13:45 AM »
Hi!
Dataflow is supposed to be able to be constrained, however in SDMXStructureDataflow.xsd the DataflowType does not contain a ConstraintType Element, however i notice that in the ECB SDMX service...
http://sdw-ws.ecb.europa.eu/Dataflow/2136672
the dataflow has a Constraint element i cannot access through XMLBeans...
(neither 2.0, or 2.1 has a constraint element)...
has anyone been able to access the Constraint in a dataflow with XMLBeans? or with OpenSDMX?
Regards
   James Gardner

 
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Stratos Nikoloutsos - Agilis

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Re: Dataflow Constrained?
« Reply #1 on: November 10, 2011, 01:58:08 PM »
Hi James,

In the context of SDMX 2.0, Constraints were only part of the RegistryInterface messages and not the Structure messages. Thus, there was no direct access to the Constraints through the Dataflow structure. Moreover, in terms of SDMX messages, two different messages were required in order to acquire this information.

In the context of SDMX 2.1, Constraints have become maintainable artefacts and can be included in an SDMX structure message, thus the referencing mechanism should allow for having both Dataflows and their Constraints within a single SDMX message.

Unfortunately, I do not know how OpenSDMX deals with this issue. What I know is that Eurostat's SDMX Registry deals with it programmatically and stores this relation in the database. When it comes to the presentation of a Dataflow including its Constraints (in the GUI of the SDMX Registry), the application has to perform two calls to the Registry Web Service (one for the Dataflow and one for the corresponding Constraint(s)) in order to combine them into a single set of information.

I hope I have shed some light.
Kind regards,
Stratos
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JamesGardner

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Re: Dataflow Constrained?
« Reply #2 on: November 10, 2011, 04:19:26 PM »
Hi Stratos!
Thanks for your prompt reply!
I have given up trying to use XMLBeans, and Jaxb(OpenSDMX) to parse DSDs since i found the source code to your data structure wizard... it is a lot better than the similar sax parser i was working on... i think i can modify your code and take what i like about my sax parser and add the extra behaviour to your model...

Thanks!
   James Gardner
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Ole Sørensen - Danmarks Nationalbank

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Re: Dataflow Constrained?
« Reply #3 on: November 18, 2011, 03:23:55 AM »
Hi James,

if you notice the xsd file ECB is using in the example:

http://sdw-ws.ecb.europa.eu/vocabulary/sdmx/2.0/SDMXStructure.xsd

you can see that they have added the Constraint element to the DataFlowType to their schema file. This is why their file is valid, probably because the information model allow this (I haven't checked that) but it is not implemented in the 2.0 schema files, as in other scenarios.

Regards,

Ole
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