Re: [OJB-developers] query based on example object

[Jakob B. <jbr...@ho...>]

hi thomas,

the solution in it's current state is quite simple: it only uses non null
instvars to produce EqualsToCriteria.
problems arise with primitives as the can't be null.
i thought of some kind of include/exclude lists, but it's not implemented
yet.

jakob

----- Original Message -----
From: "Thomas Mahler" <tho...@ho...>
To: "Jakob Braeuchi" <jbr...@ho...>
Cc: <obj...@li...>
Sent: Monday, March 18, 2002 9:12 PM
Subject: Re: [OJB-developers] query based on example object


> Hi Jakob,
>
> This looks like a useful feature!
> When I first implemented QueryByExample (QBE) I did only implement a
> primary key based version.
>
> I did not implement a generic solution as I found some difficulties.
> Imagine, you don't call example.setTest(11);
>
> The respective attribute will then be == 0;
>
> How can we distinguish such an "un-willed" zero from a "willed"
> example.setTest(0);
>
>
> There are similar problems for null String attributes.
>
> Did you address these problems in your solution?
>
> cu,
>
> Thomas
>
>
>
>
> Jakob Braeuchi wrote:
>
> > hi ,
> >
> > i just comitted a small feature to the cvs: building a QueryByCriteria
based
> > on an example object.
> >
> > Person example = new Person();
> > Query query;
> >
> > example.setBoss(false);
> > example.setTest(11);
> > example.setName("Br%");
> > query = new QueryByCriteria(example);
> >
> > this will build a QueryByCriteria with the following criteria:
> > boss = false AND test=11 AND name like "Br%"
> >
> > i didn't want to change the class QueryByExample nor the method
> > newQuery(Object obj) of class QueryFactory because
> > QueryByExample uses the Identity to retrieve Objects. Actually
> > QueryByExample could be renamed QueryByIdentity...
> >
> > jakob
> >
> > _______________________________________________
> > Objectbridge-developers mailing list
> > Obj...@li...
> > https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
> >
> >
> >
> >
>
>
>