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-coll
ection-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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