Re: [Scrollkeeper-devel] Unique identifiers

[Ali A. <ali...@au...>]

* Dan Mueth (d-...@uc...) wrote at 01:20 on 28/11/00:
> > We talked about this issue previously and we thought about an ISBN like
> > ID generated by a server available throughout the internet. This server
> > would generate unique IDs on request by document creators.
> 
> Alan and Daniel were kind enough to pop in on IRC to discuss scrollkeeper
> yesterday and the conversation quickly moved to UUID's.  They recommended
> (as Ali does) creating a UUID for each unique document.  Here a unique
> document is probably a {doc, version, language, format} quadruplet, or
> possibly even a superset of this.  It should uniquely specify the
> resource.  We will need to decide where this belongs in the OMF, perhaps
> an attribute to IDENTIFIER (ie. IDENTIFIER.UUID).  The UUID will be the
> database key.  To make things simple, we can ship a script which generates
> a UUID with scrollkeeper.  For systems with uuidgen, it will use that.  
> For other systems, we may want it to request one from a server which runs
> uuidgen (as suggested by Ali).  

It is important to point out that the UUID should not change for each
/version/ of a doc. If you have a doc and then update it, it will have the
_SAME_ uuid but a diff. version number, in my opinion. (by default, if you
just use UUID you will get the "latest" doc.)

Also - different formats should have the same UUID. They are the same
document, so they will have the same _METADATA_ (i.e. same author, same
version, same category, etc.)

Translations can have different UUIDs.

This means to get an "instance" of a doc you would need the UUID of the doc,
the version # (by default if no version is provided you get the "latest"
(greatest) version), and the format (theoretically, you could have the server
take a DocBook XML file and convert it on the fly to HTML for the user (sound
familiar?) its the same doc, just different "presentation" of the data)

> Having this UUID system will keep things simpler when we implement server
> catalogs and share docs/metadata between machines.
> 
> I'm worried that trying to generate UUID's by hand using some system as
> suggested by Rich will make things more complicated and less unique.

Rich made his suggestion because he wants to be able to "easily" refer to
UUIDs...This shouldn't be the case. You don't refer to a book's ISBN number,
you refer to its title.

> Just for completeness, I'll mention that we also want another ID number
> which we associate with each document.  We need a name - perhaps "docid"
> or "nuid" (non-universally unique id).  Multiple versions, languages,
> formats, etc. of the same document should have the same NUID.  This allows
> us to do things like look for a given document in another language, look
> for a newer (or older) version of a given document, and look for a
> different format of a document (like PS so we can print it). Perhaps we
> could call this IDENTIFIER.NUID in the OMF.

I disagree. We just need one unique ID (at least for now)...

I have a feeling if you implement multiple IDs it will confused doc authors
and just complicate matters unncessarily (if it is determined later on we need
it, then it can be added).

Regards,
Ali