semweb | Generic Scala/ScalaJS semantic web library

I tried out your mapping file and it works correctly. Your current mapping file transforms the data in the spicy to upper case and generates the specified RDF triples. Since the function grel:toUpperCase is included in the RMLMapper by default, you don't need to functions.ttl to specify these functions. This is only necessary if you want to add your own custom functions. An overview of all included functions in the RMLMapper can be found here: https://rml.io/docs/rmlmapper/default-functions/

1. Download the latest RMLMapper from our Github repository: https://github.com/RMLio/rmlmapper-java/releases
2. Run it as: java -jar -m mapping.rml.ttl
3. I get the output which is listed below.

mapping.rml.ttl

The mapping rules are already quite good, I did the following improvements:

1. rr: should not be used as prefix for your own TriplesMaps. The rr prefix is defined by the R2RML specification. To solve this, I added @base http://example.org and removed the rr prefix of the TriplesMaps:

Based on my first glance at the docs, I think you should try passing an atom instead of a Prolog string, i.e.

I think I figured out. multifile and rdf_meta do work together. The bug in the code was related to the fact that I had defined foo in rdf_meta as foo(r). I think that expansion was causing confusion at compile time with regards to pattern match. Changing the definition to foo(-) fixed the problem. Hope this helps someone in the future.

Prolog is not a functional language. This implies 2+3 does not evaluate to 5 and is just a term that gets meaning from the predicate that processes it. Likewise, ex:bob is just a term that has no direct relations to modules or predicates. Only predicates such call/1 will interpret this as "call bob in the module ex".

Next to that, (SWI-)Prolog (most Prolog's, but not all) have term expansion that allows you to rewrite the term that is read before it is handed to the compiler. That is used to rewrite the argument of rdf/3: each appearance of prefix:local is expanded to a full atom. You can check that by using listing/1 on predicates that call rdf/3 using the prefix notation.

See also rdf_meta

First, don't use GROUP BY when you don't use aggregates in the results. MySQL allows you to use it without aggregates, but it produces random results. I assume you're using it here because including userExcludedArticles table gave you duplicates of the rows. That's not the proper way to handle it.

As your query is now written it will check every row in userExcludedArticles against every row in articles/tag/tagmap and if there is a row which doesn't have the article id it can be shown. This is why the articles aren't hidden.

You need to use NOT EXISTS clause to check for this:

In your current mapping you aren't iterating using the id attribute. Since your iterators are