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From: Tony Giaccone <tgiaccone@gmail.com>
Subject: Re: AddPrefetch
Date: Mon, 14 Oct 2013 08:47:46 -0400
To: "user@cayenne.apache.org" <user@cayenne.apache.org>

In fact the promotion offer chain table is a table which contains keys for t=
hree other tables and is used to link those three. A key in that table would=
 have to be all three elements and so we choose to not specify a key.=20

Tony

> On Oct 13, 2013, at 9:25 PM, Aristedes Maniatis <ari@maniatis.org> wrote:
>=20
>> On 14/10/13 12:05am, Tony Giaccone wrote:
>>=20
>> With the prefetch in place as I singled stepped through the code, I could=
 see Cayenne making the three fetches when the call was made to performQuery=
.
>>=20
>> This line, always returned null.=20
>>=20
>> Promotion promo =3D item.getToPromotion();
>>=20
>> It wasn't till I added the join semantics that the prefetch worked and th=
e relationships where valid. My question is why?  I've never had to use join=
 semantics to prefetch to work and I wonder what it is about this configurat=
ion that requires them?
>=20
>=20
> I'd hazzard a guess and say that your one-to-one mapping of the OfferChain=
 to Promotion is related to your issue. Are you missing a primary key in Off=
erChain, instead relying on the primary key from the joined Promotion?
>=20
>=20
> Ari
>=20
>=20
>=20
> --=20
> -------------------------->
> Aristedes Maniatis
> GPG fingerprint CBFB 84B4 738D 4E87 5E5C  5EFA EF6A 7D2E 3E49 102A