On Nov 10, 2003, at 10:34 AM, Colin Putney wrote:

> If you must or prefer to use a relational database, check out Avi's 
> Roe package. It's basically the successor to Tantalus - it goes off in 
> another direction based on problems we had writing and using Tantalus.

Note that as a successor to Tantalus, Roe is fairly incomplete - it 
provides a very nice abstraction for dealing with relational data as 
relational data, but it doesn't do any kind of mapping into an object 
graph.  I still think the mapping part of the Tantalus/GLORP style of 
O/R tool is useful, and this would need to be layered  on top of Roe.  
The part I'm experimenting with ditching is the caching.  The theory, 
based on my work on Tantalus and other frameworks, goes something like 
this:

- O/R tools usually force you to use suboptimal queries, because they 
don't properly model SQL
- to make up for this, they do a lot of caching
- this caching causes lots of problems (how do you keep the data 
consistent and up to date?)
- Roe provides a solid model of SQL, which would allow you to use 
arbitrary queries with your O/R framework
- thus, you should be able to get adequate performance without caching 
anything for longer than a single transaction

Fortunately, however, all of the projects I'm currently involved in are 
using OODBs, so I haven't had much motivation to fully flesh this stuff 
out.  If anyone else is interested in pursuing an O/R mapping system 
based on Roe, let me know and I'll provide you with what info and code 
I have.

Cheers,
Avi