On Fri, 18 Feb 2005 23:15:06 +0900, Austin Ziegler <halostatue / gmail.com> wrote: > ... > Note that I'd *never* suggest that ERD should be used for object > modeling. UML Class Diagrams are perfectly good for that. But that's > about *all* they're good for, and they're not always good for that > in all languages because they make assumptions about the language > that will be used. Products like ArcStyle might be able to help with > that, but they'll still never produce a good database schema from an > object model. Never. Does this have any bearing on O/R libs such as Og and ActiveRecord? I figure it has to; it is quite unlikely that, beyond really basic scenarios, your object model will have an isomorphic fit to your database. In many cases this simply may not matter; the speed in development and the cleaner conceptual model (from a OO developers point of view) may well compensate for any inefficiencies. But I'm wondering if there are guidelines that indicate when the mismatch between the OO model and a proper E/R model is too great for any automated lib to do a good job. James