[Dspace-general] Re: [Dspace-tech] Structured metadata scheme "pretend" to be Dublin Core?
instituto A.C.Jobim
iacj at terra.com.br
Fri Apr 29 23:40:52 EDT 2005
dear Peter and Robert
I have a kind of similar problem in the Institute.
I migrated a database with some related tables into dspace.
I would like to rebuild the relationship I had (authority records) with
the new dublin core schema.
there ia a field in the dcvalue table that is never used (source_id?).
I feel very tempted to use it to store a foreing key to an authority
record.
if we had such a column we could hold some data together creating such
a structure.
Lets say:
item_id dc_type_id text_value
text_lang place source_id
xx contributor joe
en 1 1 (joe's id
in an authority record)
xx contributor.role painter en
1 1
xx contibutor mary
en 2 35
xx contributor.role dancer en
2 35
in fact I tried to create a new field just for that but dspace didn't
like it and complained.
Today we just created dc qualifiers for every kind and we are planing a
way to fill the contributors field reading from another table.
the example would be just:
contributor.painter joe
contributor.dancer mary
the other form would be more flexible because today if a new role
appears I have to create a new dc qualifier, and alter the input forms
and views.
is there any plans to include this kind of structure?
thanks Paulo Jobim
Em 2005Apr29, às 17:43, Peter Urban escreveu:
> I'm bringing this offline conversation to this list so that the
> information
> is available to anyone else facing similar challenges and to see what
> others' thoughts are. See original messages below for context. Sorry
> for the
> long post.
>
> Robert asked if there is any structure to the CDWA metadata fields. He
> says,
> "If the answer is no, CDWA is flat, you can just use and extend the
> current
> DSpace Dublin Core support to include CDWA elements." Based on his
> description, CDWA has structure. For example:
>
> CREATOR
> - IDENTITY (can be linked to an authority record)
> - ROLE
> DATE
> - EARLIEST DATE
> - LATEST DATE
>
> Do I understand correctly that a structured schema (as opposed to a
> flat
> one) cannot be added to the current metadata registry? If so, can you
> explain why? If not, and there is an option of "pretending" that CDWA
> is
> just an extension of Dublin Core, what are the pros and cons of doing
> so?
> Would we need to make a distinction between what is DC and what is CDWA
> pretending to be DC? Might there be downstream issues related to
> OAI-PMH
> support?
>
> Thanks!
>
> Peter Urban
> Kristine Fallon Associates, Inc.
> Digital Archive for Architecture System
> The Art Institute of Chicago
> purban at kfa-inc.com
>
>
>
>> -----Original Message-----
>> From: Tansley, Robert [mailto:robert.tansley at hp.com]
>> Sent: Tuesday, April 12, 2005 2:33 PM
>> To: Peter Urban
>> Subject: RE: DSpace for Art Institute of Chicago
>>
>>
>> Hello Peter,
>>
>> I'd recommend you widen this conversation to the dspace-devel
>> or -tech list as you'll get faster responses then! The model
>> of interaction around the DSpace open source community
>> doesn't tend to be people asking specific individuals for
>> help, as no one actually has general "DSpace support" as a
>> full-time job...
>>
>>> Option 2. I'm not sure I understand what you mean by
>>> "flat schema".
>>> CDWA has categories and subcategories. If you'd like to take
>>> a look -
>>> http://www.getty.edu/research/conducting_research/standards/cd
>>> wa/index.html
>>> <http://www.getty.edu/research/conducting_research/standards/c
>>> dwa/index.html
>>>> . Are you saying that if CDWA is like DC, we could extend the DC
>>>> schema
>>> within DSpace to include all of the additional CDWA fields
>>> and make them available via the customized UI in 1.2.2 beta
>>> 1? For submission and for search? What are the pros/cons?
>>
>> 'Categories and sub-categories' are orthogonal to whether a
>> schema is 'flat'. Categories are just possible values that a
>> metadata field can have.
>> What I mean is, is there any structure to the metadata fields
>> themselves?
>> e.g.
>>
>> title: Piece of work
>> author: John Doe
>> author: Jane Smith
>> abstract: This piece of work blah blah...
>> category: X123
>>
>> is flat. The following has structure:
>>
>> title: Piece of work
>> author:
>> name: John Doe
>> organisation: HP
>> author:
>> name: Jane Smith
>> organisation: MIT
>>
>> i.e. it's not just a list of name/value pairs. "Author"
>> doesn't just have one value, it has a value comprised of two
>> 'sub-parts'. My question is does CDWA contain any elements like that?
>>
>> If the answer is no, CDWA is flat, you can just use and
>> extend the current DSpace Dublin Core support to include CDWA
>> elements. The categories are more a UI concern (drop-lists
>> and the like) and the custom submit form feature (I believe)
>> supports this.
>>
>>> Option 3. I am not aware of there being an XML schema
>>> for CDWA. If we were to generate the CDWA metadata as XML,
>>> and include that XML as a bitstream in the item, and we had a
>>> crosswalk to DC, are you saying that the CDWA metadata could
>>> then be searched using an external interface into DSpace? My
>>> previous understanding was that metadata stored as a
>>> bitstream could not be searched. If it can be searched (even
>>> externally to DSpace), this sounds like it could be worth
>>> further investigation.
>>>
>>> If my understanding of Option 3 is correct, could you
>>> provide a high-level description of how this would work? For
>>> example, would we have a package of bitstreams that include
>>> the CDWA metadata XML, then import (or
>>> upload) those bitstreams as an item? How would the DC
>>> metadata be pulled from the CDWA metadata XML? How would the
>>> CDWA metadata be searched? What would happen if any of the
>>> CDWA metadata needed to be updated after the item has been
>>> archived? Can the CDWA metadata XML bitstream be modified
>>> after the item has been archived?
>>
>> If metadata is stored in an item as XML in a bitstream, it
>> means the core DSpace system itself cannot index that
>> metadata. Other systems (search engines, or DSpace add-ons)
>> that understood that XML could peer inside those XML
>> bitstreams and index the relevant data, and allow it to be searched.
>>
>> There are different APIs and protocols that those search
>> engines or DSpace add-ons can use to do this. This also
>> applies to getting the metadata into DSpace in the first
>> place, and modifying it further down the line (which is
>> possible). Basically, option 3 means that you leave DSpace
>> as is, and implement various bolt-ons that do the work with
>> CDWA via the DSpace Java APIs or network protocols. The
>> advantage of this over option 4 (hacking the
>> code) is that your code is separate from the core DSpace
>> code, and is easier to maintain; as long as the DSpace
>> APIs/protocols are backwards compatible your code will work.
>> Robert Tansley / Digital Media Systems Programme / HP Labs
>> http://www.hpl.hp.com/personal/Robert_Tansley/
>>
>>
>>
>>>> -----Original Message-----
>>>> From: Tansley, Robert [mailto:robert.tansley at hp.com]
>>>> Sent: Wednesday, April 06, 2005 10:46 AM
>>>> To: Peter Urban
>>>> Subject: RE: DSpace for Art Institute of Chicago
>>>>
>>>>
>>>> Hello Peter,
>>>>
>>>> Firstly, apologies for the delayed reply, your mail arrived just as
>>>> I
>>>> left for a 2-week business trip which meant it got snowed under.
>>>>
>>>> I'm glad to see you hope you can do this in a way that can be
>>>> contributed back to open source DSpace! This will benefit you and
>>>> the
>
>>>> Art Institute, in that you won't have to maintain the code by
>>>> yourself, the rest of the open source community will help you.
>>>>
>>>> I'm not familiar with the CDWA standard, so I'm not 100% sure how
>>>> extensive the modifications would have to be. In general, you have
>>>> a
>>>> number of options:
>>>>
>>>> * Wait for another project to implement support
>>>> for different
>>>> metadata schemas, for example the SIMILE project (simile.mit.edu).
>>>> I
>>>> suspect this won't be a good option for you, as there's no
>>>> real time
>>>> frame for when this might happen. The SIMILE project hasn't engaged
>>>> the DSpace community with any concrete plans yet, so we've no way of
>>>> knowing when this might happen. You could offer to support such an
>>>> effort.
>>>> * If the metadata standard looks somewhat like Dublin Core
>>>> (i.e. a flat schema), you can "pretend" the metadata is Dublin Core.
>>>> As of DSpace 1.2.2 beta 1, most use of Dublin Core is configurable
>>>> (e.g. which fields appear in the submission UI, advanced search
>>>> etc).
>>>> * Another option is to store the CDWA in XML
>>>> (does CDWA have
>>>> an XML Schema)? as another bitstream in each DSpace item, and have a
>>>> crosswalk that creates Dublin Core for DSpace. Other systems
>>>> interfacing with DSpace (via Java API, OAI-PMH, Web Services etc)
>>>> will
>
>>>> be able to use this metadata, though the DSpace search/retrieval
>>>> functions will use the Dublin Core. This could be treated as an
>>>> interim measure, until DSpace properly supports different schemas.
>>>> * You could just do the code gruntwork to support
>>>> CDWA in an
>>>> expedient way. This would make it difficult to fold your changes
>>>> into
>
>>>> open source DSpace though, so you'd probably end up with a "fork"
>>>> of the code
>>>> you'd have to maintain yourself.
>>>>
>>>> You certainly aren't the only project interested in alternative
>>>> metadata schemas, though, so I do hope it won't be long before a
>>>> concerted effort starts up to support this, and I hope you'd become
>>>> involved in such an effort as it would help you with your
>>>> objectives!
>>>>
>>>> Does this help?
>>>> Robert Tansley / Digital Media Systems Programme / HP Labs
>>>> http://www.hpl.hp.com/personal/Robert_Tansley/
>
>
>
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