parent and child terminology

[andimou]

R2RML specification names the rr:parent and rr:child as parent query and child query, would we keep this terminology?

Or should we skip the query part and keep them only parent and child? I have the impression when we talk we typically use these terms.

or something else? if so, what?

[pmaria]

I believe it's called parent column and child column right now. I think we should change this to parent expression and child expression. I think this matches well with the proposal in #53

[bjdmeest]

To fully match with #53, I'd suggest to use the names rml:parentMap and rml:childMap to refer to parent expression and child expression, and maybe have rml:parent and rml:child as their reference shortcut property (so they actually refer to parent reference and child reference).

If we don't do that I assume the most simple join will be of form below, as an expression means that the object should be an ExpressionMap?

ex:po rml:joincondition [
  rml:child [
    rml:reference "foreignId"
  ] ;
  rml:parent [
    rml:reference "Id"
  ]
] .

[andimou]

If I combine #59 and #53 I would think that there is no problem if we call them ParentMap and ChildMap as long as we clarify that they inherit from the ExpressionMap and not the TermMap. Namely that would allow us to use references, templates and constants but not termtype, language and datatype which feels reasonable.

cc/ @anaigmo

[anaigmo]

Oki, then summing up the proposed changes in this issue:

• Add two subclasses of :ExpressionMap: :ParentMap and :ChildMap
• Add two new properties: :parentMap and :childMap; adjusting :parent and :child to be the shortcuts

Then instead of:

ex:po rml:joincondition [
  rml:child [
    rml:reference "foreignId"
  ] ;
  rml:parent [
    rml:reference "Id"
  ]
] .

We would have without shortcuts:

ex:po rml:joincondition [
  rml:childMap [
    rml:reference "foreignId"
  ] ;
  rml:parentMap [
    rml:reference "Id"
  ]
] .

And with shortcuts:

ex:po rml:joincondition [
  rml:child "foreignId";
  rml:parent "Id"
] .

[DylanVanAssche]

This issue had a proposal and is done. Closing.