Looks like this almost works.. Setting the initial ID to Guid.Empty
definitely makes the problem go away.. I also set the mapping as:
HasMany(x => x.Items)
.KeyColumn("ShoppingListId")
.Inverse()
.Cascade.All();
Now I can add the item as such:
dbList.Items.Add(new ShoppingListItems
{
Raw = source.Raw,
UserId = identity.UserId
});
And it will create the new item. However, one small problem: The new item
does NOT get linked to dbList. Its ShoppingListId property is left as null.
Shouldn't adding a new item to dbList.Items make the ShoppingListId get set
to the primary key of dbList? Or, do I have to manually specify this?
Thanks!
Mike
On Tue, Jan 21, 2014 at 1:32 AM, Pete Appleton
<[email protected]>wrote:
> A few things that cross my mind:
>
>
>
> 1. You'll definitely need an appropriate Cascade style for the "HasMany"
> mapping on ShoppingLists.Items, e.g. SaveUpdate - not sure which mapping
> system you're using, so don't know the exact syntax
>
> 2. 99% of the time, this mapping should be 'Inverse'
>
> 3. It looks as you're manually assiging a new ID to the new
> 'ShoppingListItems' object, which I suspect is causing NH to believe that
> the new object is persistent.
>
>
>
> My general pattern for this sort of thing is as follows (pseudo-code for
> interesting bits only):
>
>
>
> class ShoppingList {
>
> Guid Id { get; protected set; }
>
> ISet<ShoppingListItem> Items { get; protected set; }
>
>
>
> public ShoppingList() {
>
> this.Items = new …
>
> }
>
> }
>
>
>
> class ShoppingListLine {
>
> Guid Id { get; protected set; }
>
> public ShoppingList List { get; protected set; }
>
>
>
> ShoppingListLine(ShoppingList list) {
>
> this.List = list;
>
> this.List.Items.Add(this);
>
> }
>
>
>
> void Delete() {
>
> if(this.List != null) this.List.Items.Remove(this);
>
> this.List = null;
>
> }
>
> }
>
>
>
> var dbList = ….;
>
> var newItem = new
> ShoppingListLine(dbList); // ctor
> handles association maintenance
>
>
>
>
>
>
>
> /Pete
>
> *From:* [email protected] [mailto:[email protected]] *On
> Behalf Of *Mike Christensen
> *Sent:* 21 January 2014 00:47
> *To:* nhusers
> *Subject:* [nhusers] Adding a new item to a collection using Fluent
> NHibernate doesn't INSERT the new row in the DB
>
>
>
> (StackOverflow question in case anyone wants
> upvotes<http://stackoverflow.com/questions/21246584/adding-a-new-item-to-a-collection-using-fluent-nhibernate-doesnt-insert-the-new>
> )
>
>
>
> I have a model called `ShoppingLists` and each `ShoppingLists` has a
> collection of `ShoppingListItems` called `Items`. What I would *like* to
> be able to do is add a new item to my list as such:
>
>
>
> dbList.Items.Add(new ShoppingListItems(Guid.NewGuid(),
> identity.UserId, source.Raw));
>
>
>
> I would expect the `ShoppingListItems` to automatically be *linked* to its
> parent `ShoppingLists` class, and for NHibernate to create the appropriate
> SQL `INSERT` statement when the transaction is committed. However, instead
> I get the exception:
>
>
>
> NHibernate.StaleStateException was unhandled
>
> HResult=-2146232832
>
> Message=Unexpected row count: 0; expected: 1
>
> Source=NHibernate
>
>
>
> What I have to do instead is create the object, save it, then add it to
> the collection:
>
>
>
> var newItem = new ShoppingListItems(Guid.NewGuid(), identity.UserId,
> source.Raw);
>
> newItem.ShoppingList = dbList;
>
> session.Save(newItem);
>
> dbList.Items.Add(newItem);
>
>
>
> I'd like to eliminate the need to do this. My mappings for
> `ShoppingLists` is as such:
>
>
>
> Id(x => x.ShoppingListId);
>
>
>
> Map(x => x.UserId).Not.Nullable();
>
> Map(x => x.Title).Not.Nullable();
>
>
>
> HasMany(x => x.Items)
>
> .KeyColumn("ShoppingListId")
>
> .Cascade.Delete(); // If Shopping List is deleted, delete all the
> Items that reference this list
>
>
>
> And my mappings for `ShoppingListItems` is:
>
>
>
> Id(x => x.ItemId);
>
>
>
> Map(x => x.Raw).Length(50);
>
> Map(x => x.Qty);
>
> Map(x => x.Unit);
>
> Map(x => x.UserId).Not.Nullable();
>
> Map(x => x.CrossedOut).Not.Nullable();
>
>
>
> References(x => x.Recipe).Column("RecipeId");
>
> References(x => x.Ingredient).Column("IngredientId");
>
> References(x => x.ShoppingList).Column("ShoppingListId");
>
>
>
> I've tried playing around with `Cascade.All()` on each, to no avoid. Any
> ideas?
>
>
>
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