Validating daml+oil-ex.daml

From: Jeff Heflin (
Date: 10/31/01

Hi everyone,

Some of my students have tried running the daml+oil-ex.daml example [1]
through BBN's DAML Validator [2] and suprisingly received 27 indications
of potential problems. Fortunately, many of these errors are due to
limitations of the validation tool, but a few are errors in the example.
Below, I discuss the errors found by the Validator, and for each suggest
whether the bug is in the Validator or the example.

1) The Santa example creates an associatedData of type xsd:real, but XML
Schema does not define a real datatype. This should probably be changed
to xsd:decimal, xsd:float, or xsd:double in the example.

2) The Person class has a restriction stating the a person can have only
one FullTimeOccupation, but FullTimeOccupation is not defined in the
ontology. The FullTimeOccupation class should be added to the ontology.

3) BigFoot is an rdfs:Class instead of a daml:Class. However it is used
in the domain of intersectionOf, which requires a daml:Class, generating
a domain type mismatch error. The example should be changed.

4) The Validator raises an error because hasMom is samePropertyAs
hasMother, but hasMom is an ObjectProperty and hasMother is a
UniqueProperty (which could be an ObjectProperty or DatatypeProperty).
Personally, I don't think this should be an error; it should only be an
error if you say an ObjectProperty is samePropertyAs a DatatypeProperty.
I'd like to get the committee's opinion on the situation.

5) The Validator raises errors anytime a cardinality restriction is
violated. In the case of the example, this is mostly because Adam,
Santa, Peter, and Ian do not have any parents mentioned. I don't think
an error should be raise here, because other values for the property may
be found on other web pages. One possibility, is to raise an error only
when a maximum cardinality constraint is violated, but even in this
case, it is possible that an as yet undiscovered equivalentTo property
will be found, reducing the total number of distinct values. Therefore,
I suggest that all violations of cardinality constraints be presented as
warnings (not errors), but would like feedback from the rest of the

6) The Validator generates a number of errors because it doesn't support
the daml:collection parse type yet. Hopefully, that will be fixed in the
near future.

What this situation indicates to me, is that we need a much clearer
description of exactly how should treat a DAML document, i.e., what
results in an error, what results in a warning, etc. Do you think this
is an issue for the Joint Committee or the WebOnt working group?



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