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Mark Diggory commented on DS-893: --------------------------------- Bill, I think exploring this would be a great idea and would possibly align us more easily with Fedora Objects. The value would be formally capturing the relationship (for instance in Fedora would be described in RELS-INT) such that it is more formally defined, for instance, recasting "bundles" as "relations": then there can be more than one relation assigned to a bitstream. <bitstream-a1> ds:isDerivativeOf <bitstream-a> <bitstream-b1> ds:isDerivativeOf <bitstream-b> However, I believe that visibility and accessibility we should seek to refine/extend the resourcePolicy types so that ResourcePolicies can be defined that identify who the Bitstream should be visible to. I will also add that other attributes can be captures int he "bundle" or "relation" table that are more metadata centric Primary <bitstream-a> ds:isPrimaryBitstream "true" Ordering <bitstream-a> ds:order "0" <bitstream-b> ds:order "1" Or alternatively <bitstream-a> ds:nextSibling <bitstream-b> <bitstream-b> ds:nextSibling <bitstream-c> Another benefit is that Bitstream.getParent would return the correct object container "Item" rather than its current mis-implementation which skips over its real container, the Bundle, to return the Item. I would like to get the Domain model out for DSpace 1.8 with Bundle still in it, then see how we would need to change that Domain Model to accomplish what you suggest... See: http://scm.dspace.org/svn/repo/modules/dspace-core/trunk/api/src/main/java/org/dspace/content/ > suggestion for a re-implementation of Bundles in the DSpace data model > ----------------------------------------------------------------------- > > Key: DS-893 > URL: https://jira.duraspace.org/browse/DS-893 > Project: DSpace > Issue Type: Improvement > Components: DSpace API > Affects Versions: 1.8.0 > Reporter: Bill Hays > > Preliminary ideas for a new implementation of "Bundle" in the DSpace data > model > Current database model relationships: > Item <- Item2Bundle -> Bundle <- Bundle2Bitstream -> Bitstream > Current java object model relationships: > Item <-> Bundle <-> Bitstream > Proposed database model relationships (1): > Item <- Item2Bitstream -> Bitstream(id, ..., bundlename, ...) > or even more succinctly: > Item <- Bitstream(id, item_id, bundlename, ...) > In current DSpace, there is no realized benefit from the container complexity > in the current model for Bundles. > This first step in the proposal removes the Bundle table and directly > associates Bitstream to Item. The concept of "bundle" is replaced by an enum > field in the Bitstream that identifies a bundle type (ORIGINAL, THUMBNAIL, > etc). Functionally this is very similar to what we get now: A bitstream > belongs to one item and is associated with one bundle. The bundle names are > not constrained, but some names are expected in various parts of the > codebase. > > Proposed database model relationships (2): > Item <- Bitstream -> MBundle(id, name, collection_id, derivative ...) > This variation replaces the bundlename enum with a new class and database > table "MBundle." Here bundles are not implemented as containers but are an > associated type concept for a bitstream. With the association to a > collection, bundles can be managed per collection or use a default set. > Other properties of MBundle can be added to further enhance management > capabilities, e.g.: > isDerivative - identify bundles for Thumbnails and DerivativeText > isVisible - indicate that the related bitstreams should be visible in > display contexts > isReserved - such as for very large "source" objects not for display or > filtermedia > [needs work - how complex does bundle "metadata" need to be?] > > Issues: > Primary Bitstream Id: This is currently only used for the ORIGINAL bundle, > so conceptually there is one per item. Note that the current model (API and > database) allows for multiple ORIGINAL bundles which therefore allows > multiple primary bitstream ids; however, the implementation doesn't expose > this possibility. > Possible replacement API calls, depending on the implementation: > item.setPrimaryBitstream(Bitstream b) > bitstream.isPrimary(Boolean b) > Various db solutions: > item.primaryBitstreamId - not standard database normalization but > consistent with dspace practice > item2bitstream.primaryBitstream - a boolean, standard normalization but > requires some management to avoid duplicates > mbundle.primaryBitstreamId - not standard database normalization but > consistent with dspace practice > item.primaryBitstream - a boolean, standard normalization but requires > some management to avoid duplicates > > In the event that someone has used primaryBitstreamId in non-ORIGINAL > bundles for special purposes, only 3 or 4 would work. > Affected Java code: Item and Bitstream would need to be adjusted. This is > fairly low-level so should not be visible to much of the API. Group > authorizations would need some work (this has not been fully analyzed). > Custom code that uses the API might be affected. Custom SQL such as for > reporting might break, but the replacement is shorter code. Collection > management of bundles types would need a new tab on the collection page > (XMLUI). > > Upgrading a DSpace instance: The database can be modified with queries. No > affect on assetstores. > > Benefits: > Simpler, more concise model which removes unused/unnecessary containership > structure. > Enhanced bitstream management with bundle properties. > Enumeration of names instead of uncontrolled strings, preventing typos in > bundle names (e.g. from ItemImport) > Provides easy solution to making derivative bitstreams visible. > Moving bitstreams between bundles does not require deleting and re-adding > the bitstream. > Fixes data model problem with primary bitstream and multiple bundles with > the same name > Drawbacks: > Not a backwardly compatible change. A fundamental change to the data > model. > Custom SQL code connecting using bundles will require rework. > Summary: > Bundles are categories for Bitstreams and do not need to be imlemented as > containers. > Bundles could be improved with added metadata and management features. > The current Bundle implementation may not be a priority issue to merit the > work suggested. However, the ideas > above may be suggestive for other work, including metadata for all DSpace > objects and exposing the data model > to external systems (e.g. Fedora) -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: https://jira.duraspace.org/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira ------------------------------------------------------------------------------ Achieve unprecedented app performance and reliability What every C/C++ and Fortran developer should know. Learn how Intel has extended the reach of its next-generation tools to help boost performance applications - inlcuding clusters. http://p.sf.net/sfu/intel-dev2devmay _______________________________________________ Dspace-devel mailing list Dspace-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dspace-devel