Re: [Scrollkeeper-devel] Unique identifiers

[Dan M. <d-...@uc...>]

On Mon, 27 Nov 2000, Laszlo Kovacs wrote:

> Hi All,
> 
> During the category tree discussion the issue of unique identifiers for
> docs was raised. As we want to keep the various discssions as focused as
> possible I decided to start this thread.
> 
> Here are the main issues raised:
> 
> (Rich Morin)
> 	http://www.geocrawler.com/lists/3/SourceForge/6429/0/4716298/
>         Each package (and each variant and version of same)
>         should have a unique identifier, so that we can be
>         clear and unambiguous in referring to it.  This is
>         really the same issue as the database folks have... 
> 
> (Rich Morin)
> 	http://www.geocrawler.com/lists/3/SourceForge/6429/0/4716421/
> 	Use mnemonic identifiers such as package name and principal developer:
> 	e.g:	perl-lw
> 
> (Ali Abdin)
> 	http://www.geocrawler.com/lists/3/SourceForge/6429/0/4718805/
> 	Use uuid-gen.
> 
> (Rich Morin)
> 	http://www.geocrawler.com/lists/3/SourceForge/6429/0/4719633/
> 	uuid-gen is not available on every platform (notably FreeBSD).
> 
> 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).  

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.

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.

Dan