Fedora Digital Object in a Nutshell Sandy Payette, Executive Director UK Fedora Training London January 22-23, 2009

Fedora Digital Objects Flexible object model can support –Documents, articles, journals –Electronic Scholarly Texts –Digital Images –Complex multimedia publications –Datasets –Metadata –Learning objects –More… Create “networks” of objects using RDF –Define object relationships and other properties via RDF –Collection/member; part/whole; etc.

DC Persistent ID RELS-EXT AUDIT n n Reserved Datastreams Custom Datastreams (any type, any number) Fedora Digital Object – Notional View POLICY

What is a PID? A Persistent Identifier (PID) Syntax – namespace:name – Examples – demo:42 – nsdl:MyImage – hdl:2000%2F2000 – uuid:34b706b4-f a0a8acb25

Object Properties “Data or Service Definition orService Deployment “A”, “I”, or “D” (Active, Inactive, Deleted)‏ “Any string” “ T19:59:03.001Z” (UTC, ISO8601 format)‏ “Any string” ‏ System generates value Either way Client provides value LEGEND “namespace:name PID Object Type State Label Content Model Created Date Last Modified Date Owner ID PID

Datastream The “content” component within a digital object representing a typed sequence of bytes Content can be stored: – Locally Inline XML Managed – Remotely Externally Referenced Redirected

Datastream Properties Version Any XML “NCName” unique within the object “X”, “M”, “E”, or “R” (Inline XML, Managed, Externally Referenced, or Redirected)‏ “A”, “I”, or “D” (Active, Inactive, Deleted)‏ “true” or “false” 1 or more System generates value Either way Client provides value LEGEND Datastream Datastream ID State Control Group Versionable

Each Datastream Version has... Version ID Created Date MIME Type Label Size Checksum Type Format URI Content Location Alternate IDs Any XML “NCName” unique within the object “ T19:59:03.001Z” (UTC, ISO8601 format)‏ An integer (number of bytes)‏ "DEFAULT", "DISABLED", "MD5", "SHA-1/256/385/512", "HAVAL", TIGER", "WHIRLPOOL". “type/subtype” (any, registered or not)‏ Any URI Any set of URIs “Any string” Internal ID or External URI for any sequence of bytes Checksum “Any string” conforming to rules of ChecksumType

Managed Fedora stores and manages the content bytestream. Content located via internal ID Fedora stores a reference (URL) to the content and mediates access to the content Fedora stores a reference (URL) to the content, but will not mediate access to content. Fedora stores a name-spaced block of XML content within the Fedora digital object XML wrapper file. Sidebar: An implementation detail on Datastreams External External Redirected Inline XML

RDF for Object-to-Object Relationships

Digital Objects... with compositional relationships

Forming Collections… with relationships to member objects PID5 PID3 PID2 isMemberOfCollection Query PID1 isMemberOfCollection Collection Object (link to FOXML – export view) (link to FOXML – ingest view) (link to FOXML – export view)

XML Serialization for Digital Objects Ingest and Export formats –FOXML –METS –ATOM –ORE (planned) –Extensible to accommodate new XML formats FOXML is the internal storage format –Simple XML format directly expresses Fedora object model –Defined by an XML schema –Easily translated to other well-known formats

Questions and Discussion