I've reinvented the wheel, there's a discussion of 'paginating'
database queries here
http://weblog.jamisbuck.org/2007/4/6/faking-cursors-in-activerecord
On Oct 2, 12:38 pm, Mike Barton <[EMAIL PROTECTED]> wrote:
> Sorry that should be
> Customer.each_in_chunks_of(100) { |cust| # Do something with cust }
>
> On Oct 2, 12:37 pm, Mike Barton <[EMAIL PROTECTED]> wrote:
>
> > Thanks for all your replies, they were very insightful.
> > The reason I was using SQL is because I didn't want all the active
> > record models loaded into the memory at once. I hadn't thought of
> > breaking the data into chunks using offsets, which would solve this
> > problem, I mean I could use pure Ruby. I refactored your solution John
> > to make something that could be added to any AR model
>
> >http://gist.github.com/14338
>
> > Which could then be used as
>
> > Customer.each_in_chunks_of{ |cust| # Do something with cust }
>
> > This doesn't allow for code like Comments.approved as in your example
> > though.
>
> > On Oct 2, 12:29 pm, John Leach <[EMAIL PROTECTED]> wrote:
>
> > > Oh, and I meant to mention, in comparison to my proposed solution, this
> > > one executes one query whereas mine executes (total number of rows /
> > > 100) queries.
>
> > > What's bad with mine is that MySQL does the query on the whole table on
> > > every loop and then just sends you the batch you asked for. With a big
> > > table, this is really bad.
>
> > > Anyone know a good way of having ActiveRecord models do this kind of
> > > execute and fetch on each, rather than get the whole lot at the start?
> > > It's clearly preferable sometimes.
>
> > > John.
>
> > > On Thu, 2008-10-02 at 12:19 +0100, Carl Drinkwater | 29degrees wrote:
>
> > > > Hi John,
>
> > > > > Nice - that's a very tidy solution. I'm assuming the each method on
> > > > > res
> > > > > fetches the rows one at a time from the MySQL server, rather than
> > > > > grabbing them all at once.
>
> > > > Yeah, exactly.
>
> > > > Regards,
> > > > Carl.
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