From: Robert Klemme <shortcutter@...>
Date: 2007-06-05T23:25:06+09:00
Subject: Re: Asking for style critics: Collecting the result of a query

On 05.06.2007 16:12, Ronald Fischer wrote:
> May I ask some kind soul to criticize the following piece of code?
> I don't have that much experience with Ruby yet, but I feel I could
> do it simpler than that.
> 
> Problem: Fetch result of a query (it happens to be a SQL query to a
> database, but the essential point here is that I need to generate
> the resulting lines piecewise, each iteration returning the next 
> row as an array of values). The result should be returned as a 
> matrix (i.e. array of arrays). In practice, the number of rows returned
> will be well below 1000, each row containing around 10 items.
> 
> Here is my code:
> 
>     def fetch_result(querystring)
>       result=[]
>       qres = dbhandle.query(qstr)
>       while row = fetch_result.fetch_row # deliver next row
>         result.push row # add row to the result array - is this OK?
>       end
>       result # return result array
>     end
> 
> I suspect there might be an overhead in appending to an array
> new rows piecewise as I'm doing it here. Is there a better way
> to do it? 
> 
> Ronald

Your sample seems to be missing something: Where does "fetch_result" 
come into existence?  And why don't you use "qres"?

Attempting to answer your question, if you just append rows without 
modification you might as well do fetch_result.to_a.

Kind regards

	robert