Bob and Dave,

Just caught up with these posts. Last year, I discovered some work on XBRL in OWL from a project called Bronto in Europe. A screenshot of an example from Bronto, using TopBraidComposer is shown below:

The N3 for the above:

:AccruedLiabilitiesTotal
      a       owl:Class ;
      rdfs:subClassOf :IFRS_GP_Item ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:hasValue "INF" ;
                owl:onProperty :decimals
              ] ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:allValuesFrom xsd:nonNegativeInteger ;
                owl:onProperty :precision
              ] ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:allValuesFrom xsd:integer ;
                owl:onProperty :decimals
              ] ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:hasValue "credit" ;
                owl:onProperty :balance
              ] ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:hasValue "INF" ;
                owl:onProperty :precision
              ] ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:cardinality "1" ;
                owl:onProperty :accruedLiabilitiesTotalValue
              ] ;
      rdfs:subClassOf
              [ a       owl:Restriction ;
                owl:hasValue "instant" ;
                owl:onProperty :periodType
              ] .

XBRL Links classes:

An example of usage:

<IFRS_GP_CalculationLink rdf:ID="ifrs-gp_Calculation_BalanceSheetClassified--AssetsCurrentTotal_to_CashAndCashEquivalents">
    <to>CashAndCashEquivalents</to>
    <order>9.0</order>
    <weight>1.0</weight>
    <role>http://xbrl.iasb.org/int/fr/ifrs/gp/role/BalanceSheetClassified</role>
    <from>AssetsCurrentTotal</from>
</IFRS_GP_CalculationLink>

Note that the 'froms' and 'tos' are strings.

The base uri for this work is http://nets.ii.uam.es/bronto/ifrs-gp. Bronto can be found at http://www.tifbrewery.com/tifBrewery/writing.htm#BRONTO

I will need to find time to look over this work again to assess what it all means in the light of the discussions you are having.

When I was at IBM, I was involved in the first versions of XBRL, as IBM's representative in the specifications work. I recall discussion on making XBRL more expressive but the constraints of XML and XSD were ever present. Expressing XBRL in OWL remains a keen interest of mine.

Bob DuCharme wrote:

Hi Dave,

One question is the namespace for describing XBRL instances. Is it better to the preexisting xbrli <http://www.xbrl.org/2003/instance> namespace instead of a generic XBRL namespace?

Even though that namespace wasn't designed specifically for use in the predicates of RDF triples, it's the namespace defined by the standard, so I'm going to go with that for now instead of defining yet another namespace. If a specific XBRL ontology gets any traction, I'll use it instead of defining another one and relying on the presence of OWL awareness to map equivalences.

It might be worth adding datatypes to the literals, e.g.

"-6"^^xsd:integer

Yeah, I was thinking about adding one for the rdf:value value, and then realized that there are several other numbers and dates in there that may also benefit from explicit typing.

XBRL Linkbases use XLink to refer to element definitions in XBRL Schemas. The URI for the schema depends on the server it has been copied to, e.g. the EDGAR archive. It may be better to use the target namespace for the schema and element name, in place of the schema URI and element definition id.

This is just the kind of thing that has me concentrating on the instance documents for now and forgetting about the XBRL taxonomy documents for now. I'll defer to your judgment!

Bob

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Ralph Hodgson
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