how to create aggregation on a graph from CONSTRUC

2019-07-15 04:56发布

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This is my query:

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rs: <http://www.welovethesemanticweb.com/rs#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
    construct {
  ?subject0 rs:similarityValue ?similairty0.
    ?subject1 rs:similarityValue ?similairty1
}
WHERE {

  {
  ?subject0 ?predicate0 ?object0.
  rs:Impromptu_No._1 ?predicate0 ?object0.
    ?predicate0 rs:hasSimilarityValue ?similairty0Helper.
    BIND(?similairty0Helper * (4/9) AS ?similairty0)
    FILTER (?subject0 != rs:Impromptu_No)  
  }
  union {
    ?subject1 ?predicate ?object.
    ?object ?predicate1 ?object1.
    ?predicate1 rs:hasSimilarityValue ?similairty1Helper.
    rs:Impromptu_No._1 ?predicateHelper ?objectHelper.
    ?objectHelper ?predicate1 ?object1
      BIND(?similairty1Helper * (1/9) AS ?similairty1)
    FILTER (?subject1 != rs:Impromptu_No._1)
  }
}

and the result is:

rs:5th_Symphony
      rs:similarityValue
            0.011111111111111112e0 .

rs:Polonaise_heroique
      rs:similarityValue
            0.011111111111111112e0 , 0.17777777777777778e0 , 0.26666666666666666e0 .

rs:Preludes
      rs:similarityValue
            0.011111111111111112e0 , 0.26666666666666666e0 , 0.17777777777777778e0 .

rs:Requiem_Sequentia
      rs:similarityValue
            0.011111111111111112e0 .

rs:Le_nozze_di_Figaro
      rs:similarityValue
            0.011111111111111112e0 .

rs:Symphony_No._29_in_A_major
      rs:similarityValue
            0.011111111111111112e0 .

rs:Piano_Concerto_No._24
      rs:similarityValue
            0.011111111111111112e0 .

rs:Impromptu_No._1
      rs:similarityValue
            0.26666666666666666e0 , 0.17777777777777778e0 .

rs:Sonata_Pathetique
      rs:similarityValue
            0.011111111111111112e0 .

rs:Dies_Irae
      rs:similarityValue
            0.011111111111111112e0 .

rs:Piano_Sonata_No._31
      rs:similarityValue
            0.011111111111111112e0 , 0.26666666666666666e0 .

rs:Violin_Concerto_No._5_in_A_major
      rs:similarityValue
            0.011111111111111112e0 .

As you see, for each instance, there are many values, I want to aggregate them and make the SUM of them for each instance. I would do that with SELECT, but with CONSTRUCT, I didn't know how to apply the aggregation.

After reading, i found that we can't use the aggregation directly from CONSTRUCT, but i'd need to use SELECT and CONSTRUCT together, it seems i have to use something named "named graph" but i didn't know how to do that even i tried.

your help is highly appreciated.

Many thanks, best regards,

Update 1

One of the ways I've tried is:

construct {
  ?subject0 rs:similarityValue ?similairty0.
    ?subject1 rs:similarityValue ?similairty1
}
WHERE {
  GRAPH ?g  {?subject0 rs:similarityValue ?similairty0}.
  {
  ?subject0 ?predicate0 ?object0.
....

but i got empty results

1条回答
劳资没心，怎么记你
2楼-- · 2019-07-15 05:18

First, it's probably better to make sure that you can select all the information that you're trying to retrieve. It looks like you're aiming for something like this:

prefix rs: <http://www.welovethesemanticweb.com/rs#>

select distinct ?s ?weight ?factor where {
  #-- ?x is the special value of interest.  This
  #-- is pulled out into a VALUES block just for
  #-- convenience; there's just one place to change
  #-- rs:Impromptu_No._1, now.
  values ?x { rs:Impromptu_No._1 }

  #-- find ?s which are "one step" away from
  #-- a common property/value with ?x, and
  #-- take 4/9 as ?weight.
  {
    ?s ?p ?o .
    ?x ?p ?o .
    bind(4/9 as ?weight)
  }
  union
  #-- find ?s which are are "two steps" away from
  #-- a common property/value with ?x, and take
  #-- 1/9 as ?weight
  {
    ?s ?a ?b . ?b ?p ?o .
    ?x ?c ?d . ?d ?p ?o .
    bind(1/9 as ?weight)
  }

  #-- get the similarity factor of the property
  #-- and make sure that ?s is different from ?x.
  ?p rs:hasSimilarityValue ?factor .
  filter(?s != ?x)
}

-----------------------------------------------------------------------------------------------------------------------
| s                                   | weight                     | factor                                           |
=======================================================================================================================
| rs:5th_Symphony                     | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Dies_Irae                        | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Le_nozze_di_Figaro               | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Piano_Concerto_No._24            | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Piano_Sonata_No._31              | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Piano_Sonata_No._31              | 0.444444444444444444444444 | "0.6"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Polonaise_heroique               | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Polonaise_heroique               | 0.444444444444444444444444 | "0.4"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Polonaise_heroique               | 0.444444444444444444444444 | "0.6"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Preludes                         | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Preludes                         | 0.444444444444444444444444 | "0.4"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Preludes                         | 0.444444444444444444444444 | "0.6"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Requiem_Sequentia                | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Sonata_Pathetique                | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Symphony_No._29_in_A_major       | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
| rs:Violin_Concerto_No._5_in_A_major | 0.111111111111111111111111 | "0.1"^^<http://www.w3.org/2001/XMLSchema#double> |
-----------------------------------------------------------------------------------------------------------------------

Now, it seems like after this, you want to group by by the value of ?s and sum the weighted similarities:

select distinct ?s (sum(?weight * ?factor) as ?similarity) where {
  values ?x { rs:Impromptu_No._1 }
  {
    ?s ?p ?o .
    ?x ?p ?o .
    bind(4/9 as ?weight)
  }
  union
  {
    ?s ?a ?b . ?b ?p ?o .
    ?x ?c ?d . ?d ?p ?o .
    bind(1/9 as ?weight)
  }

  ?p rs:hasSimilarityValue ?factor .
  filter(?s != ?x)
}
group by ?s

----------------------------------------------------------------
| s                                   | similarity             |
================================================================
| rs:5th_Symphony                     | 0.044444444444444446e0 |
| rs:Piano_Concerto_No._24            | 0.044444444444444446e0 |
| rs:Requiem_Sequentia                | 0.044444444444444446e0 |
| rs:Dies_Irae                        | 0.044444444444444446e0 |
| rs:Piano_Sonata_No._31              | 0.31111111111111117e0  |
| rs:Symphony_No._29_in_A_major       | 0.044444444444444446e0 |
| rs:Le_nozze_di_Figaro               | 0.044444444444444446e0 |
| rs:Violin_Concerto_No._5_in_A_major | 0.044444444444444446e0 |
| rs:Sonata_Pathetique                | 0.044444444444444446e0 |
| rs:Preludes                         | 0.48888888888888893e0  |
| rs:Polonaise_heroique               | 0.48888888888888893e0  |
----------------------------------------------------------------

Finally, since you've got the values that you're looking for, you can now construct the triples that you want:

construct {
  ?s rs:similarityValue ?similarity
}
where {{
  select distinct ?s (sum(?weight * ?factor) as ?similarity) where {
    values ?x { rs:Impromptu_No._1 }
    {
      ?s ?p ?o .
      ?x ?p ?o .
      bind(4/9 as ?weight)
    }
    union
    {
      ?s ?a ?b . ?b ?p ?o .
      ?x ?c ?d . ?d ?p ?o .
      bind(1/9 as ?weight)
    }
    ?p rs:hasSimilarityValue ?factor .
    filter(?s != ?x)
  }
  group by ?s
}}

@prefix :      <http://www.semanticweb.org/rs#> .
@prefix rs:    <http://www.welovethesemanticweb.com/rs#> .
@prefix rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix owl:   <http://www.w3.org/2002/07/owl#> .
@prefix xsd:   <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs:  <http://www.w3.org/2000/01/rdf-schema#> .

rs:5th_Symphony  rs:similarityValue  0.044444444444444446e0 .

rs:Polonaise_heroique
        rs:similarityValue  0.48888888888888893e0 .

rs:Preludes  rs:similarityValue  0.48888888888888893e0 .

rs:Requiem_Sequentia  rs:similarityValue
                0.044444444444444446e0 .

rs:Le_nozze_di_Figaro
        rs:similarityValue  0.044444444444444446e0 .

rs:Symphony_No._29_in_A_major
        rs:similarityValue  0.044444444444444446e0 .

rs:Piano_Concerto_No._24
        rs:similarityValue  0.044444444444444446e0 .

rs:Sonata_Pathetique  rs:similarityValue
                0.044444444444444446e0 .

rs:Dies_Irae  rs:similarityValue  0.044444444444444446e0 .

rs:Piano_Sonata_No._31
        rs:similarityValue  0.31111111111111117e0 .

rs:Violin_Concerto_No._5_in_A_major
        rs:similarityValue  0.044444444444444446e0 .
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