It is not a bad idea, it is just that you need to understand what it means to put the association on the other end.It is very natural for the wishlist to have a user property, because it is in its own table. When you have a one to many association, by definition it is not on the same table, so it goes as a separate statement.
If you don't want bidi, then you uni on the many to one side seems natural. On Wed, Oct 22, 2008 at 2:29 AM, Tim Barcz <[EMAIL PROTECTED]> wrote: > Can you expound a bit...I'm thinking about this in the context of someone > new to DDD. My thought is that a WishList belongs to a user. We don't > typically care about wishlists by themselves, we only care about them in the > context of a user. > > Can you explain why this is a bad idea and I'd want the unidirectional the > other way? > > > On Tue, Oct 21, 2008 at 7:10 PM, Ayende Rahien <[EMAIL PROTECTED]> wrote: > >> It is not bad, the problem is that you are trying to make it >> unidirectional in the wrong direction. The way this works is that the >> wishlist belongs to a user. This means that you usually have the uni >> directional from that, and query from the user if you need to. >> That is a good idea anyway, since that means that you start thinking about >> things like unbounded result sets. >> >> >> On Tue, Oct 21, 2008 at 5:54 PM, Tim Barcz <[EMAIL PROTECTED]> wrote: >> >>> Below are the mapping files....however the problem I see is that I want >>> to do a unidirectional mapping. There are two tables (Users and WishLists), >>> of which WishLists has a foreign-key ref back to users. A Wishlist doesn't >>> exists outside the context of a user. I'm reading some places where this is >>> "bad" in NH. I would like to keep this unidirectional as it feels more >>> correct. >>> >>> Suggestions. >>> >>> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" >>> namespace="NHWishList.Model" assembly="NHWishList"> >>> <class name="User" table="Users"> >>> <id name="UserId" column="UserId" type="Int32" unsaved-value="0"> >>> <generator class="native" /> >>> </id> >>> <property name="First" column="First" length="50" not-null="true" >>> /> >>> <property name="Last" column="Last" length="50" not-null="true" >>> /> >>> >>> <bag name="WishLists" cascade="all" lazy="true"> >>> <key column="UserId"/> >>> <one-to-many class="WishList"/> >>> </bag> >>> </class> >>> </hibernate-mapping> >>> >>> <?xml version="1.0" encoding="utf-8" ?> >>> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" >>> namespace="NHWishList.Model" assembly="NHWishList"> >>> <class name="WishList" table="WishLists"> >>> <id name="WishListId" column="WishListId" type="Int32" >>> unsaved-value="0"> >>> <generator class="native" /> >>> </id> >>> <property name="Name" column="Name" length="50" not-null="true" >>> /> >>> <many-to-one name="Owner" column="UserId" class="User" >>> not-null="false" /> >>> </class> >>> </hibernate-mapping> >>> >>> >>> On Tue, Oct 21, 2008 at 10:46 AM, Gabriel Schenker <[EMAIL PROTECTED] >>> > wrote: >>> >>>> show your mappings please >>>> >>>> >>>> On Tue, Oct 21, 2008 at 5:44 PM, Tim Barcz <[EMAIL PROTECTED]> wrote: >>>> >>>>> Ok that's well and good...so I've got unidirectional going on....but am >>>>> seeing strangeness >>>>> >>>>> NHibernate: INSERT INTO Users (First, Last) VALUES (@p0, @p1); select >>>>> SCOPE_IDENTITY(); @p0 = 'Tim', @p1 = 'Barcz' >>>>> NHibernate: INSERT INTO WishLists (Name, UserId) VALUES (@p0, @p1); >>>>> select SCOPE_IDENTITY(); @p0 = 'Sample', @p1 = '' >>>>> NHibernate: UPDATE WishLists SET UserId = @p0 WHERE WishListId = @p1; >>>>> @p0 = '8', @p1 = '1' >>>>> >>>>> Why does this have to be three calls? After the first call, the second >>>>> should have the ID from the first (the userId). The update should be >>>>> unnecessary. >>>>> >>>>> Tim >>>>> >>>>> >>>>> On Tue, Oct 21, 2008 at 1:40 AM, Gabriel Schenker < >>>>> [EMAIL PROTECTED]> wrote: >>>>> >>>>>> first of all to decrease complexity I would only use uni-directional >>>>>> relations in my domain model (even though in the database any relation is >>>>>> bi-directional) that is, a wishlist does not have to know any thing >>>>>> about a >>>>>> user or about its manager >>>>>> >>>>>> >>>>>> On Mon, Oct 20, 2008 at 11:16 PM, Tim Barcz <[EMAIL PROTECTED]>wrote: >>>>>> >>>>>>> I have a user object and the user can have a number of wishlists. >>>>>>> >>>>>>> Instead of having methods on user (ie. User.AddWishlist, >>>>>>> User.RemoveWishlist), I have a WishListManager which has these methods >>>>>>> on >>>>>>> it. >>>>>>> >>>>>>> Persistent entities include, WishList and WishList item, which relate >>>>>>> back to the user through the WishListManager. >>>>>>> >>>>>>> How would I set up this mapping in NHibernate? Can someone point me >>>>>>> in the right direction? >>>>>>> >>>>>>> Tim >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> >>> >>> >> >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/nhusers?hl=en -~----------~----~----~----~------~----~------~--~---
