Design item link schema

[strogonoff]

Implement universal registry item linking format, e.g. using an informal URN.

• Possibly support relative (any item in the same registry, but possibly in another subregistry) and absolute (item in another registry altogether) link formats
  • Capture item ID, item class and subregistry ID for relative links, and registry ID for absolute links
  • Provide functions to convert between link formats
• Update basic registry item schema to capture imported item source (handled in Support item source in basic registry item schema #2)

[strogonoff]

@ronaldtse

It looks like informal URN namespaces should still be registered[1][2]. Should we provision a single namespace for all registers? Or require that each register has its own namespace, which would be configured by register/registry manager in metadata?

A single namespace could presumably help us distinguish all registers that conform to our schema, though I don’t know how registration works and whether someone else can use this namespace without our input.

If we go with a single namespace, perhaps it could reference Relaton (e.g., urn:relaton) or something else universal enough. Then, register URN could looks something like urn:relaton:register:6e8bc430-9c3a-11d9-9669-0800200c9a66. Presumably absolute item links could use URNs of the form urn:relaton:register:<register_id>[:subregister:<subregister_id>]:<item_id> (potentially item IDs might have to be scoped with item class ID as well, but not yet sure).

[strogonoff]

(Assigning you as well, since if we need to register a namespace it might require action by Ribose or Relaton.)

[strogonoff]

I am not sure if we will support relative links. It looks like there is no strong precedent for relative URNs[1][2].

That would make it easier in a way, since we can be certain that any relation/link between register items will be fully qualified.

[ronaldtse]

Agree with something like this:

urn:relaton:register:<register_id>[:subregister:<subregister_id>]:<item_id>

Potentially we could try something as you suggested like urn:metaregistry:... and link it to a resolver for registry items.

Each register should definitely be namespaced.

[strogonoff]

Agree with something like this:

urn:relaton:register:<register_id>[:subregister:<subregister_id>]:<item_id>

Potentially we could try something as you suggested like urn:metaregistry:... and link it to a resolver for registry items.

Each register should definitely be namespaced.

@ronaldtse

That works. The top-level namespace ("relaton" or otherwise) may need to be registered, right? And as you noted, it may better be registered by a non-profit organization.

Should we commit to registration and implement linking when we have the namespace?

If registration takes a while or we are not sure about committing to this, is there something that prevents us from using the desired namespace for linking right now, before it is registered?

(If so, we can start with a shared informal namespace, but that means we would have to perform data migration on all registers to convert links from that namespace to our chosen and registered one.)

[ronaldtse]

@strogonoff as discussed let's use urn:relaton:... for now and we could request a namespace registration for relaton.