Hi,
I'm new raco user. Can I write datalog programs under raco?

I tried to write datalog programs and get logical plan by using Myria Demo Service. It worked for simple datalog queries, for example, "A(x,z) :- R(x,y), R(y,z)". But when I was trying "CC(x,$Min(z)) :- CC(x,z), Edges(x,z) " or "TC(x,z) :- TC(x,y), Edges(y,z)", there were some exceptions. It seems the same predicate can not be in both head and body? I'm wondering how should I write datalog programs under raco?

Thank you.