花了一天时间让狗狗找了下，找到一下open-source工具:
1. Datalog Educational System
(an open-source implementation to be used for teaching Datalog in courses) http://www.fdi.ucm.es/profesor/fernan/des/
2. XSB http://xsb.sourceforge.net/
还有propositional rule-based systems
3. Drools http://drools.jboss.org/
4.Jess
(a rule engine for the Java platform - it is a superset of CLIPS programming
language.) http://herzberg.ca.sandia.gov/
5. Jena (算不算?)
a Semantic Web framework which includes a Datalog implementation as part of
its general purpose rule engine, which provides OWL and RDFS support. http://jena.apache.org/
6.Cascalog in Clojure (算不算?)
a Clojure library for querying data stored on Hadoop clusters http://cascalog.org/
Prolog/Datalog以前最主要的一个局限memory花销太大，因此不能用来处理大数据，最
近有什么发展解决了这个问题吗？
