On Jan 25, 7:28 pm, "Allen" <[EMAIL PROTECTED]> wrote: > The basic idea of a persistence layer (as I understand it) is that you > attempt to isolate applications from the database to the point that the > application and the data model can vary independently without requiring > major code changes. As the paper above puts it, a well build > persistence layer for an application should allow moving tables, > renaming tables, renaming columns, and reorganizing tables without > affecting the applications that access them.
yeah....to be honest, one thing that makes SA unique from most other ORMs ive seen is that its specifically *not* trying to accomplish that. as you said, youre not so optimistic about it either. my experience is that those who argue about the "object-relational impedance mismatch", for which you can find endless blog/academic articles about, seem to be obsessed with a completely clean separation of objects and database. and that implies that theyd like their application to scurry along doing everything it does without nary a shadow of a relational concept being revealed....so...why use a database at all then ? SA's goal is absolutely not to create a programming paradigm or framework which allows pure separation of application/persistence concerns...such a framework could certainly build on top of SA, but within SA we are providing more primitive operations than that. The goal of SA is strictly to provide a rich framework for issuing SQL statements to a database. the ORM part of it, which is totally optional, then takes a straightforward approach to mapping Python classes to database tables and other selectables, and provides maybe the *beginning* of an abstractional layer, but thats about it. it assumes Python is a flexible enough language that its up to the larger framework to figure out where to hide the "session.query()" calls, if thats whats desired. personally I dont really believe in a pure abstractional layer and i think the more time one spends being obsessed with it, the less one ends up getting done. lump it in there with all those other silver bullets. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
