Hi all,
I think that SPARQL queries using property paths which include the plus
sign yield incorrect results. This is what I get with the following
queries (number of results between brackets):
SELECT DISTINCT ?scl WHERE {wd:Q3336843 rdfs:subClassOf* ?scl} (25 rows)
SELECT DISTINCT ?scl WHERE {wd:Q3336843 rdfs:subClassOf+ ?scl} (4 rows)
SELECT DISTINCT ?scl WHERE {wd:Q3336843 rdfs:subClassOf{1,} ?scl} (24 rows)
SELECT DISTINCT ?scl WHERE {wd:Q3336843 rdfs:subClassOf{2,} ?scl} (20 rows)
SELECT DISTINCT ?scl WHERE {wd:Q3336843 rdfs:subClassOf{3,} ?scl} (17 rows)
...
This is the output of EXPLAIN on the first and second queries (the
latter 3 have apparently the same plan as the first one):
----------------------------
{
Precode:
0: __all_eq := Call __all_eq ( #/Q3336843 )
5: BReturn 0
Transitive dt dir 1, input: (__all_eq)
input shadow: (ZÁ^D)
output: (_::trans_obj_1_1)
{
RDF_QUAD 1.8 rows(s_1_4_t0.S, s_1_4_t0.O)
inlined P = ##subClassOf , S = k_ZÁ^D
After code:
0: _::trans_subj_1_0 := := artm s_1_4_t0.S
4: _::trans_obj_1_1 := := artm s_1_4_t0.O
8: BReturn 0
Subquery Select(_::trans_subj_1_0, _::trans_obj_1_1)
}
Distinct (_::trans_obj_1_1)
After code:
0: scl := := artm _::trans_obj_1_1
4: BReturn 0
Subquery Select(scl)
After code:
0: scl := Call __ro2sq (scl)
5: BReturn 0
Select (scl)
}
----------------------------
----------------------------
{
RDF_QUAD 8 rows(s_1_2_t0.O)
inlined P = ##subClassOf , S = #/Q3336843
Distinct (s_1_2_t0.O)
After code:
0: scl := := artm s_1_2_t0.O
4: BReturn 0
Subquery Select(scl)
After code:
0: scl := Call __ro2sq (scl)
5: BReturn 0
Select (scl)
}
----------------------------
Have you already encountered this issue? I'm using build
f609f14aa6bdb8ef29d4da038fdb7934c6ca65d7.
Thanks,
Nicola
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