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Subject: Re: [cmis] Scope of Hierarchical Properties
Hi, I agree with Julian's statements. Since David C. expressed an interest in use cases I could volunteer two very common use cases to the discussion that I happen to come across frequently. (1) Thumbnails After loading a document into a CMIS enabled repository it would be great to have an CMIS application add a number of thumbnails in various sizes into a "thumbnail" structure. Since the thumbnails themselves semanticly should not be treated as an individual document, since this would clutter the namespace the thumbnails should be treated as structured meta-data. (2) Persisting and Querying XMP [1] Since many modern file formats (PDF, JPEG, ...) support XMP data upon ingestion the XMP information could (probably should) be extracted by a repository (or any thirdparty CMIS app). This should be done in a fashion that allows for query of the respective information, since of course XMP holds a wide variety of potentially very useful information. While I do not necessarily advocate the inclusion of hierarchical properties in v1.0 of the specification I think the above are fairly straight forward common use cases that could be considered. regards, david [1] http://en.wikipedia.org/wiki/Extensible_Metadata_Platform On Tue, Dec 16, 2008 at 6:09 PM, Julian Reschke <julian.reschke@greenbytes.de> wrote: > Hi, > > this certainly looks like a feature set that will be hard to standardize. > > Maybe it makes sense to look at how others have dealt with it? > > 1) JCR doesn't have structured properties per se, but can support complex > hierarchies of content nodes. So the structure is not *in* the properties, > but in the tree of nodes they are contained in. > > This approach is very flexible, and also solves the issue of queryability. > On the other hand, it's also hard to implement on top of systems that do not > happen to support this in the first place. > > 2) WebDAV properties can complain arbitrary XML, thus any kind of hierarchy > *can* be represented inside a WebDAV property (*). This is extremely simple > to implement in a repository (essentially it can treat those properties as > strings, with only one additional flag stating it's XML). > > The drawbacks here are that the property can only be manipulated and > access-controlled in total, and that there's no solution for query (yet). > > ...both approaches are flexible and can represent just anything; but because > of their flexibility clients and servers are more tightly coupled (because > they need to understand the specific format/structure). > > BR, Julian > > (*) Of course binary values would be problematic... > > > -- > <green/>bytes GmbH, Hafenweg 16, D-48155 Münster, Germany > Amtsgericht Münster: HRB5782 > > > --------------------------------------------------------------------- > To unsubscribe from this mail list, you must leave the OASIS TC that > generates this mail. Follow this link to all your TCs in OASIS at: > https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php > -- Visit: http://dev.day.com/
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