From: Kirk Haines <khaines@...>
Date: 2005-04-08T00:39:41+09:00
Subject: Re: In-depth schema details in ActiveRecord

Jason Foreman wrote:

> I'm also new to Ruby and RubyOnRails.  Coming from Java, we have the
> benefit of the JDBC standard that most db drivers followed reasonably
> well.  The metadata provided by the driver could give me tons of
> useful info.  Does such a construct exist in Ruby (DBI?)  that could
> be leveraged in something like AR?  I notice that AR has various
> adapters for different databases, this might provide some insight.
> I'll try to dig into all this over the weekend.

Ruby does have a DBI implementation.  The ORM I primarily use and develop on
(Kansas) uses it because it was a very simple way to gain usability with a
variety of database backends.

The biggest drawback to using DBI, and the reason, I assume, why neither AR
nor Og do, is performance.  Purpose built adapters to connect an ORM right
with the low level driver for a given database are going to perform better
(faster, less RAM usage) than going through DBI.

In practice, the DBI tax has not been a problem for me, but one of my goals
is to make a set of purpose build adapters available for Kansas so that one
may use them instead of DBI for supported databases (which will probably
initially be MySQL, PostreSQL, and SQLite2&3) because I can forsee it
potentially being a problem in the future.


Kirk Haines