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gbv / daia

Specification of Document Availability Information (DAIA)
http://gbv.github.io/daia/
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Implication of service 'presentation' by service 'loan'? #26

Closed lahmann closed 8 years ago

lahmann commented 8 years ago

In a recent discussion (https://github.com/vufind-org/vufind/pull/521) the question arised whether DAIA implementations should show the service presentation if the service loan is also available.

As loan somehow implies presentation (the item can be picked up and used in the library) one could argue that presentation does not need to be shown as a service (especially as the service loan without the implied service presentation is quite unusual)?

olli-gold commented 8 years ago

In my opinion DAIA should not decide, which implications are common or not; it should only show availabilities without implications. A service should be listed, if its availability is known, so that no assumptions or implications need to be done with the DAIA output. That being said, its only consequent to set the service presentation to available for items, that can be lent and are available for loan. Setting it to unavailable would be false, not setting it would omit a service, which could in fact get set.

lahmann commented 8 years ago

@olli-gold, I am not disagreeing with your point of view, the reason for asking this question is whether even records that need to be requested from stack would need to be assigned the service presentation as it would be possible for the user to lend the requested item and use it in the library. If the presentation service is conceptualized this wide it would (imo) be necessary to provide a hint in the specification: as long as an item that's for loan is not impossible to use in the institution (as e.g. in archives which do not provide a reading room) the service presentation must be provided.

nichtich commented 8 years ago

loan does not imply presentation, especially if limitations apply. However I'd expect to be able to use a book "within the institution or department" (presentation) also if I get it for use "outside of the institution or department for a limited time [after] having been picked up there" (loan).

The question whether to show presentation service in addition to loan service is another issue, this fully depends on the client and usability. I'd show presentation in addition to loan only if it comes with less limitation, delay, and/or href.

question is whether even records that need to be requested from stack would need to be assigned the service presentation as it would be possible for the user to lend the requested item and use it in the library.

In this case both presentation and loan come with href (need to be requested). With the display rule suggested above, presentation would be hidden by the client because its not "better" than loan.

provide a hint in the specification: as long as an item that's for loan is not impossible to use in the institution (as e.g. in archives which do not provide a reading room) the service presentation must be provided.

Ok, a DAIA server should not assume any implications between services such as loan => presentation but include all possible or known services and let the client decide how to reduce this list.

lahmann commented 8 years ago

Thanks for the clarification! The addition to the specification is precise and covers this issue.

lahmann commented 8 years ago

Has the specification been updated with the above mentioned note regarding implicated services?

nichtich commented 8 years ago

Here the 0.9.9 version of the spec:

A DAIA server SHOULD NOT omit services because of assumed implications between service types (for instance most times an item is available for loan it is also available for presentation) but include all service types it knows about.

lahmann commented 8 years ago

Great! Thanks!