Folks, (01)
This discussion raises some of the same points as Ed Barkmeyer's
note in the thread "FW: Big Data Logic Stack?" (02)
I sent a slightly edited version of Ed's note and my response to the
conceptual graph email list. Jack Park responded with some pointers
to the Cascalog web site. (Copy below with my response to Jack.) (03)
Datalog is essentially a subset of Prolog that is designed for
processing a database. It has a much cleaner notation for logic
than the SQL WHERE clause or SPARQL. It also avoids the nonlogical
features of NULL values in SQL or the filters of SPARQL. (04)
If the DAML project had adopted Datalog as their primary notation
back in 2005, they would have a foundation that could support both
relational and graph databases with equal facility. (05)
People who don't know logic never liked Prolog. They keep designing
rule-based languages with an English-like front end. Back in the
1990s, Norbert Fuchs and his students developed ACE as an English-like
front end to Prolog (or Datalog). (06)
Fuchs and his students also adapted ACE as a front end to OWL, and
all the software is available for a free download. For more info,
see the Wikipedia article on ACE: (07)
http://en.wikipedia.org/wiki/Attempto_Controlled_English (08)
Recommendation: Adopt Datalog as the interface to both relational and
graph DBs. Use ACE as a foundation for an English-like interface to
the Semantic Web, RDBs, and rule-based languages. (09)
John
_______________________________________________________________________ (010)
On 2/3/2013 1:13 AM, Jack Park wrote:
>> Two interesting links which appear to be related are these:
>>
>http://nathanmarz.com/blog/introducing-cascalog-a-clojure-based-query-language-for-hado.html
>> and
>> https://github.com/nathanmarz/cascalog (011)
Thanks for those pointers. (012)
Cascalog looks like a good adaptation of Datalog to Hadoop. (013)
In the early 1980s, Ted Codd came across Prolog, and his immediate
reaction was "I wish I had invented that." (014)
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