[Fiware-ngsi] QueryContext proposal

[Bisztray, Denes (NSN - HU/Budapest)]

Hi All,

 

I quite like the xls, thanks for the constructive feedback and expansion!

 

The only part I would refine a bit is the exclusivity of ID as an identification method. I'm not sure if it is a good idea to have one designated metadata that decides a match. I propose one modification:

 

The ID will be a prominent element, i.e. the current xls stays, but we cater for such cases when ID is not present in the attribute list, i.e. exact match of metadata, partial match of metadata is considered. The effect are essentially the same as the ID match and ID non-match.

 

Updated excel is attached.

 

Best,

Dénes

 

 

 

From: ext Haller, Stephan [mailto:stephan.haller at sap.com] 
Sent: Thursday, March 01, 2012 5:26 PM
To: Bisztray, Denes (NSN - HU/Budapest); ext Tobias Jacobs; Martin Bauer; Farkas, Lorant (NSN - HU/Budapest); Zamani Farahani, Armin; fiware-ngsi at lists.fi-ware.eu; Tschirschnitz, Fabian
Subject: RE: QueryContext proposal

 

All,

 

I have taken Denes input and added a few cases and compiled it to an Excel sheet as a basis for further discussion. Using Excel helps avoiding formatting issues you sometimes have when tables are included directly in e-mails.

 

To move forward, we should in my opinion use the following approach:

1.       Agree that tables in the Excel sheet cover all potential cases

2.       Agree how each case should be handled (fail / no fail)

3.       Agree on the REST details (error codes, operation to use)

4.       Update the Binding Word document with all the details

 

Some of the assumptions I made - on which we obviously also need to agree:

1.       A request should either be completely successful or fail (Atomicity). Handling of partially successful calls (e.g., "2 out of 3 attributes added") would become a nightmare (both on the client as well as for consistency reasons)

2.       Use the ID meta data attribute to check if two attributes are the same or not. If we have more than one attribute of the same name, they MUST have meta data with an ID, else we cannot distinguish them.

 

Regards,

-Stephan

 

 

 

From: Haller, Stephan 
Sent: Donnerstag, 1. März 2012 10:07
To: 'Bisztray, Denes (NSN - HU/Budapest)'; 'ext Tobias Jacobs'; 'Martin Bauer'; 'Farkas, Lorant (NSN - HU/Budapest)'; Zamani Farahani, Armin; 'fiware-ngsi at lists.fi-ware.eu'; Tschirschnitz, Fabian
Subject: RE: QueryContext proposal

 

Denes,

 

I am in a long meeting all day today, so I will look at this carefully in the evening or tomorrow. One quick remark regarding the meta data match: I think we need to look at specific meta data elements - a match on something like "ID" or "Source" would likely indicate some other action than just a match on "timestamp"....

 

Any yes, I do realize that this is complicating things... :-(

 

Regards,

-Stephan

 

 

From: Bisztray, Denes (NSN - HU/Budapest) [mailto:denes.bisztray at nsn.com] 
Sent: Donnerstag, 1. März 2012 08:48
To: Haller, Stephan; ext Tobias Jacobs; Martin Bauer; Farkas, Lorant (NSN - HU/Budapest); Zamani Farahani, Armin; fiware-ngsi at lists.fi-ware.eu; Tschirschnitz, Fabian
Subject: QueryContext proposal

 

Hi all,

Here is my proposal for the queryContext semantics. 

PLEASE READ CAREFULLY before replying. 

Attribute mass replace scenario (either contextElements or /{contextElement}) level.

Note: the input as per page 22/sec.5.4.6.1 we assume only a set of ContextElements with the contained attributes and the update action type.

Note: in case the input ContextAttribute set of a ContextElement contains a set of ContextAttributes of the same name, then that ContextElement will fail in the ContextElementResponse structure with 400 Bad Request. (this is why the multiple value input with no metadata is not considered)

1.      Replace (update action), (PUT)

Input ->        One Attribute   Multiple Attibutes with same name      
        no metadata at all      exact metadata match (one result)       partial metadata match (one result)     multiple result match   exact metadata match (one result per attribute value)   partial metadata match (one result per attribute value) multiple result match  
One Attribute   replace replace Fail 409 / ?    Fail 409        Replace the matched ones        Fail 409 / ?    Fail 409       
Multiple Attributes with same name      Fail 409        replace Fail 409 / ?    Fail 409        Replace the matched ones        Fail 409 / ?    Fail 409       

Open question: what should happen to the Multiple Attribute Same Name input case with those attributes that are not matched?

2.      Append (append action), (POST)

Input ->        One Attribute   Multiple Attibutes with same name      
        no metadata at all      exact metadata match (one result)       partial metadata match (one result)     Multiple result partial match   exact metadata match (one result per attribute value)   partial metadata match (one result per attribute value) multiple result partial match  
One Attribute   Fail 400        Fail 409        Add new Add new Fail the matched ones with Fail 409, add the others     Add all Add all
Multiple Attributes with same name      Fail 400        Fail 409        Add new Add new Fail the matched ones with Fail 409, add the others     Add all Add all

3.      Delete (delete action), (DELETE)

Input ->        One Attribute   Multiple Attibutes with same name      
        no metadata at all      exact metadata match (one result)       partial metadata match (one result)     Multiple result partial match   exact metadata match (one result per attribute value)   partial metadata match (one result per attribute value) multiple result partial match  
One Attribute   Delete  Delete  Fail 409 / ?    Fail 409        Delete the matched ones         Fail 409 / ?    Fail 409       
Multiple Attributes with same name      Fail 409        Delete  Fail 409 / ?    Add new Delete the matched ones Fail 409 / ?    Fail 409       

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