On May 13, 2008, at 11:45 AM, Jeff Johnson wrote:
>
> 1) Is there an existing data model for a hierarchical store using  
> UUID's?
>
>     Note "model", not "implementation", please. I'm looking for a  
> model first
>     because real world data often has loops and other snarls that  
> the assertions
>     in a declarative model would help focus an implementaion.  
> Certainly any/all
>     hierarchical data models include the assertion
>        Every object depends on its parent /predecessor containers.
>


Let me try to state more precisely the data model I am looking for ...

There's an example of a filesystem data model with move/rmdir dynamic  
operations at

     http://alloy.mit.edu/tutorial3/alloy-tutorial.html

that could be adapted to a hierarchical data store using UUID's  
fairly simply.

The system I wish to model is sufficiently similar to a file system:
	repositories contain packages
just like directories contain files in a filesystem.

The specific property I wish to model is cache coherency, guaranteeing
through explicit assertions in the model that the client's cache is  
managed in lock-step
through a store-and-forward dynamic operation (like move/rmdir in the  
alloy filesystem
model), rather than by some other heuristic like LRU time stamp's  
attached to UUID object
instances.

I hope that clarifies the data model I am seeking, as well as the  
reason for modeling
in the first place.

73 de Jeff