From: Gary Wright <gwtmp01@...>
Date: 2007-02-09T04:46:17+09:00
Subject: Re: General Approach to Data Validation


On Feb 8, 2007, at 11:51 AM, Drew Olson wrote:

> Pit Capitain wrote:
>> The other way would be to read the records one after the other (using
>> cursors in db terminology) in an appropriate sort order. If  
>> ActiveRecord
>> allows you to do this in parallel with both tables, you could compare
>> the tables like this:
>
> This is the exact approach I originally wanted to take. I would be  
> very
> interested to know if ActiveRecord supports this type of operation. I
> have yet to see a way to do it from what I've read of the  
> documentation.

A while back (last year?) I asked why ActiveRecord didn't support
'lazy' iteration over query results.  AR slurps up the entire
result set into memory and then wraps objects (i.e. instances of
ActiveRecord::Base or subclasses) around each row.

This approach obviously has problems if you have large data sets.

Perhaps this has changed since I last posed the question?


Gary Wright