Hi, Chris and Kingsley,
thanks for the tip! We got it working now by adding the triple [1]:
<http://orcamento.dados.gov.br/sparql/> elda:supportsNestedSelect true .
The SPARQL query generated by Elda is much simpler, now. Works beautifully.
[1]
http://dev.dados.gov.br/codigo/outros/orcamento-linked-data/changeset/0eb507b1a891033cfbb60c985ccbe6017df2d435#aspecsorcamentottl_n28<http://dev.dados.gov.br/codigo/outros/orcamento-linked-data/changeset/0eb507b1a891033cfbb60c985ccbe6017df2d435>
Best regards,
Augusto Herrmann
On Thu, Jan 10, 2013 at 12:35 PM, Kingsley Idehen <[email protected]>wrote:
> On 1/10/13 7:44 AM, chris dollin wrote:
>
>> On 10 January 2013 12:03, Augusto Herrmann <[email protected]>
>> wrote:
>>
>>> Greetings!
>>>
>>> We're implementing a Linked Data API for the Brazilian federal budget
>>> [1],
>>> using Elda, in a similar way the UK government has done with some of its
>>> open data. It's still in an early alpha stage, though. What we're having
>>> difficulty with is defining the Views for the item-de-despesa [2]. In our
>>> spec [3], we can's even list all the properties lest the SPARQL query
>>> becomes too complex for Virtuoso to handle. Even with only a few
>>> properties,
>>> if the user chooses to list 25 or more items per page, the query breaks.
>>>
>>> We've looked at the schools example view [4] and it looks quite similar,
>>> but
>>> the generated SPARQL query is much simpler. Does any one have a clue on
>>> what's wrong with the views we're defining?
>>>
>>> [1] http://orcamento.dados.gov.br/
>>> [2]
>>> http://orcamento.dados.gov.br/**doc/item-de-despesa<http://orcamento.dados.gov.br/doc/item-de-despesa>
>>> [3]
>>> http://dev.dados.gov.br/**codigo/outros/orcamento-**linked-data/files/**
>>> 305212de5f6852e447ea13bae4afa5**cbf47f99b5/specs/orcamento.**ttl#L47<http://dev.dados.gov.br/codigo/outros/orcamento-linked-data/files/305212de5f6852e447ea13bae4afa5cbf47f99b5/specs/orcamento.ttl#L47>
>>> [4]
>>> http://code.google.com/p/**linked-data-api/source/browse/**
>>> trunk/examples/config/**education.data.gov.uk.ttl#35<http://code.google.com/p/linked-data-api/source/browse/trunk/examples/config/education.data.gov.uk.ttl#35>
>>>
>> Does Virtuoso implemented nested SELECTS and have you enabled them
>> in your Elda config?
>>
>> Without nested selects, the core of a View query is repeated for every
>> selected item. If the view core is big, the entire query is enormous, and
>> can blow up buffers between Elda and the SPARQL endpoint. "Enormous"
>> meaning multiple megabytes.
>>
>> Which is why Elda has the nested select option ...
>>
>> Chris
>>
>> (Stuart may have some other ideas.)
>>
>>
> Add virtuoso list to the cc.
>
> Virtuoso supports SPARQL subqueries. I've provided an example here:
> http://bit.ly/UNaKyA .
>
>
> --
>
> Regards,
>
> Kingsley Idehen
> Founder & CEO
> OpenLink Software
> Company Web: http://www.openlinksw.com
> Personal Weblog:
> http://www.openlinksw.com/**blog/~kidehen<http://www.openlinksw.com/blog/~kidehen>
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>
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>
>
>
>
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