W3C home > Mailing lists > Public > public-rif-comments@w3.org > December 2009

OntoBroker Implementation Report [Update]

From: Thomas Krekeler <krekeler@ontoprise.de>
Date: Thu, 3 Dec 2009 14:25:05 +0100
To: <public-rif-comments@w3.org>
Message-Id: <0LroEc-1OGDi705zK-013UW8@mrelayeu.kundenserver.de>

find below an updated implementation report for OntoBroker.


1.  Your name, affiliation, and (optionally) the names of other people who
helped with the implementation.

Thomas Krekeler, ontoprise GmbH

2. The name of your system, a URL for its website (if any), and a
one-sentence description.

OntoBroker 5.3
Semantic Web middleware, deductive database

3. Which dialects your software is designed to support (eg Core, BLD, PRD,
or non-standard extension dialects). We would appreciate some brief
commentary about why you chose these dialects, and what sorts of
implementation techniques (eg algorithms) are being used.

ObjectLogic Dialect (OBLD), refer to [1].
Dialect designed for ObjectLogic, ontoprise's F-logic 2 derivate.
Supports most BLD term and formula types plus some additional, in particular
default negation in rule bodies.

4. Do you believe your system currently conforms to the RIF Candidate
Recommendations? Does it pass all the test cases for your dialect(s)? If
not, which features does it lack and/or which test cases does it not yet
pass? Do you have plans to make it conformant, and make it pass all the test

OntoBroker 5.3 has been released in June 2009, the implementation has been
done some months before.
Some of the later changes haven been incorporated for the next OntoBroker
version, e.g. aggregates (even if only OntoBroker specific ones are

We are happy to see features like remote formulas, lists and constraints
which we like to adopt.
We also will make use of introducing new connectives for the schema part of
ObjectLogic, also we would even more like to see them predefined in FLD.
OntoBroker currently uses some special encodings for them as well as for
remote formulas, lists and constraints since these features have not been
available at the time of implementation.

5. Does it implement any parts of RIF RDF and OWL Compatibility? Any issues?

Neither RDF nor OWL imports are supported.

6. Did you implement the "at risk" features? If not, do you intend to, or do
you think we should remove them from RIF?

== 1-to-1 Lists ==
RDF imports are currently neither supported nor planed for OntoBroker.

== Equality in the rule conclusion  ==
OBLD doesn't allow equality in rule conclusions.
We don't intend to do so.
We would like to see this feature removed from BLD.

== Strictness Requirement ==
OntoBroker skips formulas which contain datatypes or built-ins it doesn't
support when importing a RIF document.
Currently OntoBroker has no explicit BLD or Core export.
The user has to remove/transform formulas not allowed for BLD/Core manually.
Thereby the strictness requirement is not fulfilled.
It is not planed, but we consider to implement it.

== Safeness ==
OWL imports are currently neither supported nor planed for OntoBroker.
If adding OWL support we would allow combinations only for which the
safeness restriction holds.

== Indexing from zero ==
The RIF implementation of OntoBroker 5.3 doesn't support built-ins at all.
The next version will support OntoBroker specific built-ins but no DTB
The OntoBroker specific built-ins typically start indexing from zero.

7. We'd appreciate your evaluation of whether the RIF Candidate
Recommendation is ready to proceed along the standards track toward being a
W3C Recommendation. If not, please be sure to tell us what problems you
think we need to address.

We would like to have F-logic 2 related built-ins ([1]) and formulas (e.g.
property range specifications) in DTB respectively FLD.
Besides that we think that the specification is in a good state and we don't
have any major issues.

8. Which datatypes & builtins do you support?

Supported datatypes are
rif:local (partial)
rif:text respectively rdf:PlainLiteral

The RIF implementation of OntoBroker 5.3 doesn't support built-ins at all.
The next version will support OntoBroker specific built-ins but no DTB


[2] http://forum.projects.semwebcentral.org/forum-builtins.html
Received on Thursday, 3 December 2009 13:25:35 UTC

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