[Fiware-ngsi] register context problem

[Tobias Jacobs]

Hi Denes,

NEC strongly votes for the second possibility (all Entities with all attributes). The Metadata then holds for every single Entity/Attribute combination registered.

This way you could express information like "I can provide the position and the speed of car_1, car_2, and car_3 with an accuracy of +-10%" in one ContextRegistration instance.
If the metadata information has to be more fine-grained, then one has to use multiple ContextRegistration instances.

Best regards
Tobias



From: fiware-ngsi-bounces at lists.fi-ware.eu [mailto:fiware-ngsi-bounces at lists.fi-ware.eu] On Behalf Of Bisztray, Denes (NSN - HU/Budapest)
Sent: Dienstag, 17. April 2012 10:40
To: fiware-ngsi at lists.fi-ware.eu
Subject: [Fiware-ngsi] register context problem


Dear all,

As per request I summarise my problems with the NGSI-9 registerContext.

As one can see, the request contains a list of ContextRegistration structures which contains the following (page 25, sec 5.5.7 ):

-       List of EntityIDs (optional)

-       List of ContextRegistrationAttributes (optional) - List of ContextAttributes and/or AttributeDomains which are made available through this registration.

-       List of ContextMetadata (optional)

So the problem is the following:

How do we match the EntityId set with the contextAttribute and contextMetadata set?

Possible solutions I can come up with:

-       Match by position, i.e. EntityId[4] matches with ContextRegistrationAttributes[4]. This solution is blatantly flawed, as one Entity can have only one attribute.

-       All Entities will have all attributes. This could work, but then what do we do with the contextMetadata. How do we map them to the attributes...

So I cannot really see what the designers were thinking when they came up with this message.

Best,

Dénes
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.fiware.org/private/fiware-ngsi/attachments/20120417/cdcda770/attachment.html>