Vic, probably isn't an issue for you since you only use HashMaps ;)
On Wed, 09 Feb 2005 08:12:32 -0600, Vic Cekvenich <[EMAIL PROTECTED]> wrote:
> Which I could do with a join on SQL side. I can't see how this is
> something I'd use or how it' scale, but.... I guess somone uses it.
> THANKS for the education.
> .V
>
> Kris Jenkins wrote:
>
> >
> >
> > The N+1 selects problem is when you query for n parents, and you need
> > one extra query for the children. Internally, this happens:
> >
> > List parents = sqlMap.queryForList( "getParents", parameter );
> > for ( Iterator i = parents.iterator(); i.hasNext(); ) {
> > Parent p = (Parent) i.next();
> > List children = sqlMap.queryForList( "getChild", p.getId() );
> > p.setChildren( children );
> > }
> >
> > So you end up with 1 query for the parent list, plus one extra for
> > each parent to get the children = n + 1. Rather inefficient.
> > This is the problem that 2.0.9 fixes.
> >
> > Sorry for the confusion.
> > Kris
> >
>
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