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cul / AC-RDF-Mapping

AC RDF mapping for Hyacinth fields and their MODS serializations
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Use of blank nodes in FEDORA #4

Open simosacchi opened 8 years ago

simosacchi commented 8 years ago

@barmintor @melanieWacker I have been using several blank nodes constructs in my example (for modeling info about authors, identifiers, etc.)

@barmintor Is this an acceptable approach to store that info in FEDORA? What about when we will have URIs for people for id.library? For indexing/presentation purposes do we need to replicate the info in the stored RDF descriptions or providing the URI is enough?

barmintor commented 8 years ago

Fedora supports bnodes, but it will be preferable to store these graphs elsewhere in a way that allows their reuse and linking (unless that description is strictly contextual to AC).

simosacchi commented 8 years ago

Cases may vary: for the author info this was just me dealing with the fact we do not have id.library in place and therefore no URI for authors nor the specific RDF description that would be provided following the URI.

Other constructs may be more likely to be strictly contextual to AC (e.g. RIOXX, and I am not sure about the identifier one)

Please look here for an example https://github.com/cul/AC-RDF-Mapping/blob/affiliation/10.7916:D8N0153Q.xml (and do not consider the UNI ;) )

melanieWacker commented 8 years ago

@barmintor I have a related question -- I probably should know -- but what exactly is the difference between a bnode and a local graph?

simosacchi commented 8 years ago

@melanieWacker as far as I know a local graph operates just like a blank node but it is assigned an ID that is meaningful in the local context (one that you can actually reference elsewhere in the RDF description).

barmintor commented 8 years ago

I think, for what it is worth, that the rioxx data seems maybe exclusive in use to AC, but not contextual exactly: couldn't we safely store that graph and link to it as part of a local project vocabulary?

barmintor commented 8 years ago

@melanieWacker I suspect they are the same thing (an anonymous sub-graph that cannot be referenced externally), but I am inferring what local graph means here (I am not familiar with the term).

simosacchi commented 8 years ago

@barmintor I am not opposed of storing any portion of the graph elsewhere and link to it. There might be a limited reusability of the RIOXX graph, but I can see that happening when multiple research outputs are funded under the same project.

One newbie question: how are info stored in separate (and remote) RDF descriptions being pulled in for indexing?

melanieWacker commented 8 years ago

@barmintor , regarding local graph: the term has been used in some of the Hydra working groups, e.g. here: https://wiki.duraspace.org/display/hydra/2015-09-24+Preserving+Linked+Data+-+Relying+on+URIs+--+Trey+Terrell

barmintor commented 8 years ago

Ah, ok. Yes, the hash-URIs. They are somewhat like blank nodes, though there are some subtle distinctions- for example, I don't think a triple store is obliged to preserve the particular underscored id for a blank node between serializations? These are storeable in Fedora 4 and manipulable via special patching requests.

On Thu, Apr 21, 2016 at 9:19 AM, melanieWacker notifications@github.com wrote:

@barmintor https://github.com/barmintor , regarding local graph: the term has been used in some of the Hydra working groups, e.g. here: https://wiki.duraspace.org/display/hydra/2015-09-24+Preserving+Linked+Data+-+Relying+on+URIs+--+Trey+Terrell

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barmintor commented 8 years ago

I think broadly speaking we want to distinguish between description that is truly only relevant to a narrow context (for example, ordering information, or whether a particular file is "the" schema for "the" xml document) and description that is referenced in a certain context but applicable generally.

barmintor commented 8 years ago

Though there is implied work for id.library / URI service there.