From: Hannes Wyss <hwyss@...>
Date: 2005-12-20T20:33:43+09:00
Subject: Re: [ANN] Object Database Access v 1.0 released

On Tue, Dec 20, 2005 at 07:56:14PM +0900, Pe�a, Botp wrote:
>1 it sounds great but my dumb brain cannot picture its use and it begs for examples.
One of the major problems of using a relational database when coding in
ruby, is that a RD severely restricts ruby's flexibility. I believe that
this can generally be said for using relational databases with object
oriented systems. My personal pet peeve however is the fact that with a
relational database, every simple evolution in the code-space must be
reflected in the database schema.
This problem has been addressed by the prevayler project (1) and its
ruby-implementations mnemonic and madeleine (2). I've had the pleasure to
work with both mnemonic and madeleine, but I've also run into problems,
such as:
* huge memory consumption and related performance problems (when the
  physical host starts swapping, performance degrades very quickly)
* all actions on your objects must be codified through a Command interface
  (this point is actually from http://www.rubygarden.org/ruby?Madeleine
	- it's exactly what I mean, but I would never have been able to state
	it so precisely)
* implementing search is very hard work
* I came to a point, where taking a snapshot was not possible anymore
  (a Stack Overflow Error if I remember correctly)

ODBA tries to solve these issues while keeping the flexibility of the
Object prevalence approach.

I'll try to cook up some good examples and get back to you with them.


1) http://www.prevayler.org
2) http://madeleine.sourceforge.net

Hannes

-- 
Mit freundlichen Gr�ssen / best regards

Hannes Wyss
Konzeption & Entwicklung

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