Reference Iri Choices

RDF supports different, confusingly-named approaches to resource referencing, each with tradeoffs.

TLDR: Choosing between approaches:

Use relative-path relative IRIs for maximum composability when embedding or importing meshes and submeshes
Use absolute-path relative IRIs for clearer namespace context and better support for moving submeshes within the same mesh hierarchy
Use absolute IRIs only for cross-mesh references
Relative and absolute paths both preserve relationships when moving complete meshes between domains

Absolute IRI References

Any IRI that has a scheme (e.g., http:) is an Absolute IRI

Example

This example uses two absolute IRIs, one using the "ex:" prefix for the example.com authority:

@prefix ex: <https://example.com/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

# In ns/djradon/_ref/_default/djradon_ref.trig
ex:djradon a foaf:Person ;
   rdfs:seeAlso ex:djradon/index.html .

Pros

explicit

Cons

limits transposability and composability
e.g., if you moved mesh hosting away from https://example.com, the foaf:Person and rdfs:seeAlso assertions would still refer to the original references
not ideal if you're:
- making updates
- working offline

Relative IRIs

Any IRI that lacks a scheme (e.g., http:) is resolved against a base IRI following RFC 3986. Such relative IRI references come in three distinct forms:

Network-path reference — begins with //.
- Example: //other.org/x → inherits the base’s scheme, e.g. http://other.org/x.
Absolute-path reference — begins with / but not //.
- Example: /foo/bar → keeps the base’s scheme and authority, resets the path, e.g. http://example.org/foo/bar.
Relative-path reference — does not begin with / or //.
- Example: foo/bar or ../foo → inherits the base’s scheme, authority, and path context, e.g. http://example.org/base/foo/bar.

If no base is specified, an inferred base of the requested scheme and authority is used. This behaviour is essential to Semantic Flow Best Practices.

Relative-Path Relative IRIs

@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

# In ns/djradon/_ref/_default/djradon_ref.trig
<../../../djradon/> a foaf:Person ;          # The document itself
   foaf:knows <../../alice/> ;           # A sibling node in the mesh
   rdfs:seeAlso <../bio/bio.html> .      # A resource page contained in a "bio" node under ../../djradon/

Pros

maximum composability

Cons

../../../ makes eyes swim

Absolute-Path Relative IRIs

@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

# In ns/djradon/_ref/_default/djradon_ref.trig
</ns/djradon/> a foaf:Person ;
   foaf:knows </ns/alice/> ;          # Clear namespace context
   rdfs:seeAlso </ns/djradon/bio/bio.html> .