''This page was imported from'': [[http://hera/cgi-bin/viewcvs.cgi/*checkout*/DOMS/Ingest/design/discussionPaper.tex?rev=HEAD|discussionPaper.tex]] by [[mke]]

''Author'': [[bam]]

= DOMS Objects and Object Structure Discussion =

The current (Tue Nov 21) object design and structure choices are
presented briefly and a number of questions are raised.

== DOMS Objects ==

On the page [[DOMS objects]] three basic
objects, 'Group', 'Entity' and 'Atom', are suggested. Are there
differences which merit a definition of different DOMS objects? Should
such 'top level object types' be defined in the 'contentModel'
property (in current example all objects have contentModel
'SBOBJECT')?

There is also a question of 'ordered groups', e.g. pages in a
book. There are a number of possible solutions for this...

=== Example objects ===

The 'logo1' ingest example {{{data/ingest2Test/}}} in
[[#fig|figure 1]] illustrates relations between objects.  The
image object 'close-up' illustrates the contents of a DOMS object with
type image.

<<Anchor(fig1)>>
[[http://merkur/viewvc/trunk/docs/legacy/logo1example.png?root=doms&view=co|{{http://merkur/viewvc/trunk/docs/legacy/logo1example.png?root=doms&view=co}}]]
<<BR>> <<BR>>
[[http://merkur/viewvc/trunk/docs/legacy/imageObjectExample.png?root=doms&view=co|{{http://merkur/viewvc/trunk/docs/legacy/imageObjectExample.png?root=doms&view=co}}]]

Figure 1. The 'logo1' ingest example 'from a distance' and an image object 'close-up'. Original xfig sources [[http://merkur/viewvc/trunk/docs/legacy/logo1example.fig?root=doms&view=co|here]] and [[http://merkur/viewvc/trunk/docs/legacy/imageObjectExample.fig?root=doms&view=co|here]].

== DOMS Content Model ==

The content model defines the content of one DOMS object. Different
types have different content models. Types are also DOMS objects and
all DOMS objects reference a type using the 'isObjectType' relation -
except the 'type type object'?

=== SB Objects ===

All objects are 'SB objects' and contain (see
[[DOMS Content Model]]):

  .'''Properties'''
    .'''type''' = "FedoraObject"
    .'''state''' = "A"
    .'''label'''
    .'''contentModel''' = "SBOBJECT"
  .'''Datastreams'''
    .'''Dublin Core'''
    .'''Relations'''
      .'''hasRights'''
      .'''isObjectType'''
    .'''Administrative'''
  .'''Disseminators'''
    .'''?VIDEO_PRESENTATION (start, maxMilliSecs) -> MPEG2'''
    .'''?SOUND_PRESENTATION (start, maxMilliSecs) -> MP3'''
    .'''?IMAGE_PRESENTATION (maxWidth, maxHeight) -> PNG'''
    .'''?TEXT_PRESENTATION (start, maxChars) -> UTF-8 TXT'''
    .'''Index Representation -> XML'''

The 'Fedora Object Dublin Core datastream' is specified where? The
'SB Object Dublin Core datastream' should be specified.

The page [[SB DOMS object structure]] suggests:

  .'''Additional datastreams'''
    .'''?PRESENTATION_IMAGE_150x150'''
    .'''?PRESENTATION_IMAGE_700x700'''
    .'''?PRESENTATION_IMAGE_FULL'''
    .'''?PRESENTATION_MOVINGIMAGE_PREVIEW'''
    .'''?PRESENTATION_MOVINGIMAGE'''
    .'''?MASTER'''

== Type Objects ==

Type is a subtype of SB (type type exception)?

  .'''Additional datastream'''
    .'''Type'''

The 'type datastream' is yet to be defined. The type SB (all types
subtypes of type SB) should be predefined (missing in example). Which
other types should be predefined? Suggestions: type type, type
project, type rights, type file, type logical, type image, type audio,
type video, type text, type filetype (all filetypes subtypes of type
filetype?), certain filetypes?

Would we like all type objects to have 'isObjectType relation' to type
type and introduce a 'subtype relation' (self reference issue again)?

== Rights Objects ==

Rights is a subtype of SB (hasRights exception)?

 .'''Additional datastream'''
   .'''Rights'''
     .'''seeInIndex'''
     .'''seeObject'''
     .'''accessContent'''
     .'''modifyObject'''

The 'rights datastream' should be defined.

== Non-Project Objects ==

  .'''Datastreams'''
    .'''Additional relation'''
      .'''isPartOfProject'''

This is suggested on the page [[SB DOMS object structure]]. This
suggests an 'SB project' for types and rights objects. Perhaps the
'isPartOfProject relation' should be defined for logical objects?

== File Objects ==

  .'''Datastreams'''
    .'''Additional relations'''
      .'''isFileType'''
      .'''?hasOriginal'''
  .'''Additional datastreams'''
    .'''Content'''
    .'''Technical'''

== Image/Audio/Video/Text Objects ==

  .'''Datastreams'''
    .'''Additional relations'''
      .'''?has...File'''

= Questions =

  .'''PID''' The left side should be a known project; these should be
  specified in Fedora properties; right side should be? Object renaming?


  .'''contentModel''' =SBOBJECT for all objects in example; should this
  be changed to 'top-level types'?


  .'''Dublic Core''' Language? Should format and rights be described in
  DC as well as in RELS-EXT? Last Thursday we talked about letting the
  Fedora Dublin Core be a simple 'title-holder' and then introduce an
  SB Dublin Core datastream. Why was that and should we?


  .'''RELS-EXT''' How do we avoid self-references in a nice way? Does
  'object type type' not have an 'isObjectType' relation? Do all type
  objects not have an 'isObjectType' relation? How many 'isObjectType'
  relations can one object have? Do we have a 'subType' (or a more
  general 'conceptualParent') relation?  Repeat the above questions
  with right objects and 'hasRights'. Is the 'isPartOfProject'
  relation mandatory for all non-project objects (including types and
  rights) -- do we have an SB project for types and rights? Should the
  'isPartOfProject' relation be mandatory for file objects (if we
  expect these to be referenced by multiple logical objects)? Do we
  want an explicit 'isFileType' relation in file objects or do we want
  to use the 'isObjectType' for file-type as well?

== TODO ==

  .'''Datastreams''' Rights: Usage rights (if I can access the material,
  what can I use the material for)? Creative Commons machine readable
  rights? Type datastream (type objects). Technical datastream (file
  objects).


  .'''Syntax pages''' (for doms-relations, administrative, rights,
  type and technical datastreams)