This worked like a charm and is exactly what I needed.
Thanks again!
On Jan 20, 9:34 am, Hudson Akridge <hudson.akri...@gmail.com> wrote:
> Understood. Ok, well, let's see if this works:
> HasMany(x=>
> x.CreditCards).AsBag().KeyColumn("PolNbr").PropertyRef("PolicyNumber");
>
> The PropertyRef should allow you to map to a non-key column in the parent
> table. On the References() side it allows you to map to a non key property
> in the related table. PropertyRef is for mapping lagacy data specifically.
>
> If that doesn't work, do a quick ExportTo() in your config and paste the
> hbm.xml mappings if you could, so I can make sure FNH is writing the correct
> XML.
>
> You're fortunate that you're going from Composite to a single id, and not
> the other way around. NHibernate doesn't support Hibernate's <properties>
> tag yet, which means you can only map from one column to another (hibernate
> allows you to do many columns to many columns in a property-ref)
>
>
>
> On Tue, Jan 19, 2010 at 8:59 PM, Corey Coogan <coreycoo...@yahoo.com> wrote:
> > Thanks again Hudson. I'm totally with you on the DB stuff and have
> > read quite a bit on the relationships. Unfortunately, most the tables
> > truly need a PolicyNumber and PolicyDate as the composite key. That's
> > because everytime a policy is renewed or changed in any way, a new
> > "portfolio" gets created which is a whole mess of tables with those 2
> > columns used to identify them. On the other hand, something like
> > CreditCard, is tied to a policy regardless of it's portfolio, so in
> > this case it is related to a PolicyNumber only.
>
> > I realized that the keys typically match up as a traditional foreign
> > key constraint, but that's not the way these two tables are related,
> > which is why I'm posting this question. These are tied together today
> > with a hand-rolled data access layer. The user specifies a
> > policynumber and an as of date and the following queries are executed
> > on a single open connection:
>
> > - Get the max(policydate) <= asOfDate
> > - Ge the Policy record for the PolicyNumber/PolicyDate
> > - Get credit cards for the PolicyNumber
>
> > I'm OK with specifiying a hand-written sql statement if necessary.
> > Maybe I need to handle these cases where there is no real FK in the
> > database by populating with an NH query after the initial retrieval.
> > I'm just looking for the best way to map this stuff despite the ugly
> > nature of what I'm working with. So I although I appreciate the
> > advice regarding DB design, but this is truly out of my hands.
>
> > Thanks,
> > Corey
>
> > On Jan 19, 3:44 pm, Hudson Akridge <hudson.akri...@gmail.com> wrote:
> > > By the HasMany declaration. This is a one-to-many mapping in NH lingo,
> > and
> > > I'd recommend reading up on
> > > that<
> >http://ayende.com/Blog/archive/2009/04/13/nhibernate-mapping-ltsetgt....>.
> > > NHibernate is smart enough to know what your ParentId column is on Policy
> > > when going to the child table (CreditCards), it only needs to be told
> > what
> > > column matches the ParentId in the child (CreditCards) table. In your
> > case,
> > > it's PolNbr.
>
> > > I'd recommend against using composite keys in your mapping. You don't
> > have
> > > to mirror how the database has declared things. In that case, if
> > > PolicyNumber is truly your ID, which it seems like you can do since
> > things
> > > that relate to your Policies only contain a PolicyId back to their
> > parent,
> > > then that's the only column that needs to be specified as your Id.
>
> > > Composite Keys are for when there's no other option in my opinion, and if
> > > you declare composite keys, any children tables must also have the
> > parents
> > > composite key columns contained within them to make for a valid database
> > > relationship. Since the CreditCards table appears to only have the
> > > PolicyNumber (PolNbr) then you, by database semantics, should be able to
> > > just treat a Policy as unique in the business domain by nothing more than
> > a
> > > PolicyNumber. If that wasn't a case, a CreditCard could belong to
> > multiple
> > > Policies, and in that case, the DBA has made an error and really needs a
> > > join table between Policies and CreditCards.
>
> > > On Tue, Jan 19, 2010 at 3:18 PM, Corey Coogan <coreycoo...@yahoo.com>
> > wrote:
> > > > Wait, I just realized that I may still be confused. Your example is
> > > > assigning Id(x =>, but this is a composite key. How will FNH know
> > > > that PolicyNumber=PolNbr?
>
> > > > On Jan 19, 2:37 pm, Hudson Akridge <hudson.akri...@gmail.com> wrote:
> > > > > I'm guessing that PolicyNumber/PolicyDate in Policy are mapped as a
> > > > > composite key?
>
> > > > > Is there any reason for this other than that's what the database has
> > > > mapped
> > > > > it as? Is PolicyNumber a valid entity Identifier as far as the domain
> > > > model
> > > > > is concerned?
>
> > > > > If so, then you'd just map PolicyNumber with an
> > > > > Id(x=> x.PolicyNumber).GeneratedBy.Assigned(); //Just a guess on the
> > > > > assigned thing since I think your app might generate them
>
> > > > > And map your collection like so:
> > > > > HasMany<CreditCard>(x => x.CreditCards).AsBag()
> > > > > .KeyColumn(PolNbr );
>
> > > > > Viola. Done. No need for a where at all there.
>
> > > > > Now, given that I caught a mapping. prefix, I'm assuming you're using
> > an
> > > > > automapper. I'd advise against it in your case. It's very rare to
> > expect
> > > > > automapper to automagically map for a legacy database environment.
> > Swap
> > > > to
> > > > > Fluent Mappings.
>
> > > > > On Tue, Jan 19, 2010 at 1:06 PM, Corey Coogan <coreycoo...@yahoo.com
>
> > > > wrote:
> > > > > > I have 2 entities that are described below. I want to map many
> > credit
> > > > > > cards to one policy. There is no proper FK between them in our
> > Oracle
> > > > > > DB (I can't change the DB at all). They do match up on the
> > > > > > PolicyNumber->PolNbr properties though.
>
> > > > > > I can't figure out how to map this relationship. Here's what I
> > have
> > > > > > so far, but I'm not sure how to specify the Key in the containing
> > > > > > entity that doesn't match.
>
> > > > > > mapping.HasMany<CreditCard>(x => x.CreditCards)
> > > > > > .KeyColumn(PolNbr )
> > > > > > //where to map CreditCard.PolNbr to Policy.PolicyNumber
>
> > > > > > Policy
> > > > > > {
> > > > > > PolicyNumber : string (PK)
> > > > > > PolicyDate : date (PK)
> > > > > > CreditCards : IList<CreditCard>
> > > > > > }
>
> > > > > > CreditCard
> > > > > > {
> > > > > > PolNbr : String (PK)
> > > > > > CcType : String (PK)
> > > > > > ExpDt : String (PK)
> > > > > > //3 more columns that are the PK
> > > > > > }
>
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> > > > > --
> > > > > - Hudsonhttp://www.bestguesstheory.comhttp://
> > twitter.com/HudsonAkridge
>
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