1.
Fedora migration considerations
Juliet L. Hardesty
Metadata Analyst, Indiana University
Open Repositories, June 15, 2016

2.
Fedora 3 diagram key
Repository object
Structural metadata datastream
Descriptive metadata datastream
Other metadata datastream

3.
Indiana University President's Office records, 1937-1962.
Subject files, 1937-1962. Aeons, Board of, 1939-1940.

4.
Fedora 3 - documents
VAA8877-06169 Fedora
DC
RELS-
EXT
METS
VAA8877-U-03624
Fedora
DC
RELS-
EXT
PDF
VAA8877-U-03624-001
Fedora
DC
RELS-
EXT
MASTER
Derivatives
MASTER-
MIX
Folder
Document in
folder
Page in document
isMemberOfCollection
isPartOf
isPartOf

5.
Portable soft drink stand at Bowling Green

6.
Fedora 3 - images
P02668 Fedora
DC
RELS-
EXT
METS
PURL
Redirect
isMemberOfCollection
DCMODS
Image

7.
[Program, 2013-2014, no. 117]

8.
Fedora 3 – time-based media
avalon:22187
Fedora
DC
RELS-
EXT
MODSRIGHTS
SECTIONS
TECH/DIS
PLAY
WORKFLOW
Fedora
DC
RELS-
EXT
STRUCTURE MATTERHORN
avalon:22191
Fedora
DC
RELS-
EXT
STRUCTURE MATTERHORN
Item
CD 1 CD 2
avalon:22189
isMemberOfCollection
TECH/DIS
PLAY
TECH/DIS
PLAY
isPartOf
isPartOf

9.
Focusing on Fedora 3 structure
• RELS-EXT defines structure going up
• METS or special datastreams required to
define structure going down
• All in XML as datastreams on objects that
connect together down to the digital file

10.
https://github.com/duraspace/pcdm/wiki
Portland
Common
Data
Model

11.
Document example in PCDM
Wilcox, David and Andrew Woods. “Hands-On: Seeing Fedora 4 Firsthand.” Fedora 4 Training
Workshop. Open Repositories 2015.

12.
METS: fileSec

13.
METS: structMap

14.
VAA8877-06169 VAA8877-U-03626 VAA8877-U-03626-page1
filesdocuments pages
VAA8877-U-03626Proxy VAA8877-U-03626-page1Proxy
thumb.jpg
screen.jpg
large.jpg
pcdm:
hasMember
pcdm:
hasMember
Fedora 4 structure diagram

15.
http://localhost:8080/fcrepo/rest/VAA8877-U-
03625/pages/VAA8877-U-03625-page1Proxy

16.
METS as PCDM in Fedora – SPARQL
query
select DISTINCT ?document ?firstPage ?nextPage where {
{ <http://localhost:8080/fcrepo/rest/VAA8877-06169> pcdm:hasMember ?document .
?document iana:first ?firstPageProxy .
?firstPageProxy ore:proxyFor ?firstPage .
}
union
{
<http://localhost:8080/fcrepo/rest/VAA8877-06169> pcdm:hasMember+ ?page .
?page pcdm:hasFile ?f .
?f ebucore:hasMimeType "image/jpeg"^^xsd:string .
?pageProxy ore:proxyFor ?page .
?pageProxy iana:next ?nextPageProxy .
?nextPageProxy ore:proxyFor ?nextPage .
}
}

17.
SPARQL query results for structure of
folder VAA8877-06169

18.
Transforming METS to PCDM
• Consider structure for collections using METS
• fileSec and structMap
– @GROUPID, @ID, @FILEID (unique identifiers
from both sections) in combination with <div>
structure within structMap can point to grouping
and ordering structure for objects
• Migrating easier if identifiers brought over

19.
Considerations for structural metadata
• RELS-EXT in Fedora 3 migrated to Fedora 4
• Other structure datastreams are on you to
map
• METS – possible to map programmatically but
maybe not in a standard way

20.
Descriptive Metadata - IU
MODS

21.
Fedora 4 options for descriptive
metadata: Option 1
• Migration tools
– migration-utils
– fedora-migrate gem
Neither really takes advantage of Fedora 4/external triplestore
unless original is already RDF; fedora-migrate requires Hydra
Available now, keeps all metadata, nothing lost; can have RDF
statements on object if already in RDF (fedora-migrate)

22.
Descriptive metadata to Fedora 4:
Option 2
• Map only simple statements to RDF
– Minimal descriptive metadata (title, date) or
descriptive metadata indexed for discovery (title,
date, creator, type, subject, genre, language)
– Use ontologies that allow for simple statements

23.
Descriptive metadata to Fedora 4:
Option 2
• Map only simple statements to RDF
– Minimal descriptive metadata (title, date) or
descriptive metadata indexed for discovery (title,
date, creator, type, subject, genre, language)
– Use ontologies that allow for simple statements
Not all metadata is in RDF; changes in
ontologies/standards might not be 1:1 match with original
Creates RDF statements in Fedora 4/external triplestore; great
option if metadata is DC or other non-hierarchical standard

24.
Descriptive metadata to Fedora 4:
Option 3
• Map complex/hierarchical information into
external triplestore
– All RDF statements (simple and complex) go into
external triplestore but only simple statements
are on Fedora 4 object

25.
Cushman photograph – Fedora 4

26.
Cushman photograph – external triplestore

27.
Descriptive metadata to Fedora 4:
Option 3
• Map complex/hierarchical information into
external triplestore
– All RDF statements (simple and complex) go into
external triplestore but only simple statements
are on Fedora 4 object
Separates metadata between repository and triplestore,
problematic if original metadata not kept in repository
More/all metadata available as RDF; updates easier to manage
through triplestore/Fedora 4 functionality

28.
Descriptive metadata to Fedora 4:
Almost Option 4
• MODS “unofficial standard” mapping to RDF
– MODS and RDF Group’s mapping/transformation
scenario (http://mods2rdf.xyz/)
– Available as conversion code to see MODS mapped
into Fedora 4
Work in progress (not always up, transforming few elements);
you might not agree with suggested mappings
Available now to try; might offer standard way to transform
MODS similarly across institutions

29.
Considerations for descriptive
metadata
• Current state of descriptive metadata
• Management needs of Fedora 4
• Transform to RDF statements or also to Linked
Data
• Decision: keep original descriptive metadata
or not?
– At IU, keep original descriptive metadata (for full
item view)

30.
Thank you!
• Julie Hardesty
• jlhardes@iu.edu
• @jlhardes