feature request: implementation of xsd:integer()

[egonw]

As for example in this Scholia query:

# tool: scholia
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

SELECT
  (xsd:integer(?count_) AS ?count)
  (CONCAT("Total chemicals with ", ?description_) AS ?description)
WHERE {
  BIND("haswbstatement:P31=Q113145171|P31=Q59199015" AS ?constraint)
  VALUES (?description_ ?property_query_term) {
    ("or without stereochemistry" "")
    ("fully defined stereochemistry" "P31=Q113145171")
    ("undefined stereochemistry" "P31=Q59199015")
    ("CAS registry number" "P231")
    ("canonical SMILES" "P233")
    ("InChI" "P234")
    ("InChIKey" "P235")
    ("chemical formula" "P274")
    # ("ChEMBL ID" "P592") # limit IDs
    # ("ChemSpider ID" "P661") # limit IDs
    ("PubChem ID" "P662")
    # ("KEGG ID" "P665") # limit IDs
    ("ChEBI ID" "P683")
    ("found in taxon" "P703")
    ("isomeric SMILES" "P2017")
    # ("ZINC ID" "P2084") # limit IDs
    ("crystal structure" "haswbstatement:P3636|P11375")
    ("safety classification and labelling" "P4952")
    ("mass spectrum" "haswbstatement:P4964|P6689")
    # ("SMARTS notation" "P8533") # not for now
    ("NMR spectrum" "P9405")
    # hacky way to get quantity properties.
    ("pKa" "linksto:Property:P1117")
    ("mass" "linksto:Property:P2067")
    ("solubility" "linksto:Property:P2177")
    ("melting point" "linksto:Property:P2101")
    ("boiling point" "linksto:Property:P2102")
    ("electric dipole moment" "linksto:Property:P2201")
    ("ionization energy" "linksto:Property:P2260")
    # ("minimum explosive concentration" "linksto:Property:P2204") # safety
    # ("time-weighted average exposure limit" "linksto:Property:P2404") # safety
    # ("ceiling exposure limit" "linksto:Property:P2405") # safety
    # ("maximum peak exposure limit" "linksto:Property:P2406") # safety
    # ("short-term exposure limit" "linksto:Property:P2407") # safety
    # ("solubility product constant" "linksto:Property:P11813") # less than 5 statements
  }
  BIND(CONCAT(?property_query_term, " ", ?constraint) AS ?search_query)
  SERVICE wikibase:mwapi {
    bd:serviceParam wikibase:endpoint "www.wikidata.org" ; 
                    wikibase:api "Search" ; 
                    wikibase:limit "once" ; 
                    mwapi:srsearch ?search_query;
                    mwapi:srlimit "1".
    ?count_ wikibase:apiOutput "//searchinfo[1]/@totalhits".
  }
}
ORDER BY DESC(?count)

[hannahbast]

@egonw Thanks for the example query. Can you explain the use/need of xsd:integer here`? There are three questions:

1. Why xsd:integer (which stands for integers of arbitrary size, rarely needed) and not xsd:int (integers with normal 8-byte precision)?
2. Why any conversion at all? Is the ?count_ returned by the SERVICE clause a string?
3. What does the SERVICE query do? it does not work, even on the WSQD: try it.

[egonw]

Can you explain the use/need of xsd:integer here`?

No, but the first sounds arbitrary. The wikibase:mwapi is using a special index, making it faster enough, and can possibly be removed from the Qlever version, being much faster.

I only filed it because the methods was not implemented and someone else also asked about it. I have started generalizing the Scholia code to run on the Qlever Wikidata endpoint, but running into a mix of issues.

Do you have an overview of things not implemented yet, but known? So that I know it's on your team's radar already?

[egonw]

3. What does the SERVICE query do? it does not work, even on the WDQS

It does, not before the filling in of the search_query value, a combination of a property and the haswbstatement:P31=Q113145171|P31=Q59199015 value. So, for example like this.

[joka921]

#1332 Was just merged, which adds the functions xsd:int[eger] that convert strings to ints.
They will currently however wrongly convert values that are already numeric to undefined, so I am leaving this issue open for now, until these functions are fully implemented.

[1ec5]

Did #1332 regress? I’m getting this error when querying for places and their populations in OSM:

Not supported: Function "<http://www.w3.org/2001/XMLSchema#int>" is currently not supported by QLever.

[hannahbast]

@1ec5 I have built a new index over the weekend (for the latest planet-240513.osm.pbf) and inadvertently started it with a version of QLever from a month ago. It's now the latest version again. Thanks for pointing this out to us.

PS: We are currently running some experiments on the machine hosting https://qlever.cs.uni-freiburg.de/osm-planet . So queries will be slower than usual for some periods.