techno.md

@@ -23,16 +23,18 @@
      1. [Direct Mapping]: RDB to RDF Mapping
      2. [R2RML]: RDB to RDF Mapping Language
   * [RDB2RDF implementations]:
-     * [D2RQ] `(Java)`
-     * [OpenLink Virtuoso RDF Views] `(C)`
-     * [R2RML Parser] `(Java)`
-     * [Ontop] `(Java)`
-     * [rdb2rdf] `(Python)`
-     * [Triplify] `(PHP)`
-     * [R2D2] `(PHP)`
-     * [RDF4J] `(aka Sesame)` + [r2rml-api-rdf4j-bridge] `(Java)`
-     * [Allegrograph] `(Common Lisp)`
-     * [MarkLogic] `(C++)`
+
+| Name | Language | Mapping language | Licence | Comment |
+| --- | --- | --- | --- | --- |
+| [D2RQ] | Java | D2RQ mapping language | Free |
+| [OpenLink Virtuoso RDF Views] | C | Virtuoso Meta Schema Language | Free | Mapping to external database only available in commercial version
+| [R2RML Parser] | Java | R2RML | Free |
+| [Ontop] | Java | R2RML | Free | Exist as a Protégé plugin |
+| [rdb2rdf] | Python | Direct mapping | Free |
+| [Triplify] | PHP | Direct mapping | Commercial |
+| [R2D2] | PHP | D2RQ mapping language | Free |
+| [RDF4J] aka Sesame  + [r2rml-api-rdf4j-bridge] | Java |  | Free |
+
 * RDF triplestore and SPARQL endpoint:
   * [OpenLink Virtuoso triplestore] `(C)`