I'm confused, how would grabbing chunks of a huge result set be more
efficient than grabbing the records by PK?
Couldn't you just have a select that grabbed the requested item, and
passed it back to the consumer?
Larry
On 10/3/07, [EMAIL PROTECTED]
<[EMAIL PROTECTED]> wrote:
> My problem with RowHandler is that iBATIS controls the iteration. I just say
>
> sqlMap.queryWithRowHandler ("getAllItems", rowHandler);
>
> and all items get processed by the rowHandler.
>
> But in my case I need to make iBATIS return items one-by-one when it is asked
> to do so because the framework controls the iteration.
> This is a very simplified basic logic of the framework:
>
> while (itemProvider.hasNext()) {
> Object item = itemProvider.next();
> process(item);
> }
>
>
>
> -----Original Message-----
> From: Christopher Lamey [mailto:[EMAIL PROTECTED]
> Sent: Wed 10/3/2007 11:55 PM
> To: [email protected]
> Subject: Re: how to map huge resultsets?
>
> Hmm...I don't see how having an external framework prevents you from using a
> RowHandler. Your item provider could implement the RowHandler interface and
> the external code wouldn't know or care about it. Or your item provider
> could wrap something that does implement RowHandler so the external code
> doesn't know it exists. The main point is that you can pull mapped objects
> on a row by row basis from the database.
>
> How is a RowHandler different that what you were describing in your first
> mail?
>
> On 10/3/07 3:33 PM, "[EMAIL PROTECTED]"
> <[EMAIL PROTECTED]> wrote:
>
> >
> > Thanks for your reply.
> >
> > I can't use the rowhandler callback because the iteration is external to
> > iBATIS. In my case a batch framework iteratively asks for an item and
> > processes it - and I am trying to implement an iBATIS item provider (I
> > realize
> > now I should have explained this in the initial post).
> >
> > Robert
> >
> >
> > -----Original Message-----
> > From: Christopher Lamey [mailto:[EMAIL PROTECTED]
> > Sent: Wed 10/3/2007 11:06 PM
> > To: [email protected]
> > Subject: Re: how to map huge resultsets?
> >
> > Hello,
> >
> > You should take a look at the RowHandler interface and the
> > queryWithRowHandler calls in SqlMapClient (page 61 of the pdf). Basically,
> > the RowHandler gets invoked for every row returned rather than mapping all
> > the rows into objects in a collection.
> >
> > Cheers,
> > Chris
> >
> >
> > On 10/3/07 2:37 PM, "[EMAIL PROTECTED]"
> > <[EMAIL PROTECTED]> wrote:
> >
> >> Hello,
> >>
> >> I am wondering whether it possible to implement the following scenario with
> >> iBATIS:
> >>
> >> 1. run an iBATIS-managed select
> >> 2. get a scrollable result set instead of a list of mapped objects
> >> 3. manually scroll the result set and ask iBATIS for object
> >> corresponding
> >> to current row
> >>
> >> Hibernate provides this possibility
> >> (http://www.hibernate.org/hib_docs/reference/en/html/batch.html) so I
> >> thought
> >> it would be feasible with iBATIS too, but I couldn't figure out a way. The
> >> motivation is a batch scenario where the select returns a huge number of
> >> rows
> >> so all mapped objects can't be loaded into memory at once.
> >>
> >> The iBATIS way I am aware of is to use queryForList(String statementName,
> >> int
> >> skipResults, int maxResults), but this means querying the database
> >> (TOTAL_NUMBER_OF_ROWS / maxResults) times.
> >>
> >> Can somebody give advice about pros & cons of the two approaches?
> >>
> >> Thanks
> >> Robert
> >>
> >>
> >> This message is for the designated recipient only and may contain
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> >
> >
> >
> >
> > This message is for the designated recipient only and may contain
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>
>
>
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