search

oeg-upm / morph-rdb

Virtual Knowledge Graph Creation from RDB with R2RML
https://morph.oeg.fi.upm.es/tool/morph-rdb
Other
42 stars 38 forks source link

Assumptions about type of term maps in query rewriting #19

Open frmichel opened 9 years ago

frmichel commented 9 years ago

Hi again,

By browsing through the code of the query rewriting part (morph-base-querytranslator and morph-r2rml-querytranslator), I've noticed a quite important issue: in many places you assume that subject maps are always template-based (like when trying to match a URI in subject position of a triple pattern with a subjet map), and object maps are always column-based. Which is wrong. Imagine a database with URLs in some column: a subject map could simply use this value with a rr;column property, by adding a rr:termType rr:IRI. Similarly, an object map can use a template, say to concatenate a first name and last name, and then specify a termType rr:Literal. These examples are not exotic I think.

Hope this helps ;-)

Franck.

fpriyatna commented 9 years ago

thanks Franck, I'll work on this :)

dachafra commented 4 years ago

Thanks for the value comment @frmichel, you are totally right. @jatoledo will test different possibilities (template/constant/etc) over subject/object first and see if they are already resolved