What is pw? What is pw.PreRollAdverts? Or PostRollAdverts? (you mention both). How are they mapped and what is relevant pieces of the database structure?
The answers to the questions above will affect this, but here are some starting comments: If you add the same value object to the same collection twice, NHibernate will save it twice, otherwise objects would just disappear. So what you want then is to use a collection that will ensure uniqueness, i.e. a "set" type collection. The other important thing to consider is how NHibernate can see the difference between saved and unsaved instances, see "unsaved-value". /Oskar 2011/11/30 Davec <[email protected]>: > Hi folks, > I have a very primative business object, with a single property: URL. > It's a value object so if to URLs are the same I want NH to consider > them as so and not insert another record into the DB when there is > already ready one in there for it. > > To elborate then, I have code which works which looks like: > > PostRollAdvert existingAdvert = _postRollAdvertRepository.Find(t => > t.URL == URL).SingleOrDefault(); > if (existingAdvert != null) > pw.PostRollAdverts.Add(existingAdvert); //add existing > else > { > PostRollAdvert newAdvert = new PostRollAdvert() { URL = > adFromFrontend.URL }; > pw.PostRollAdverts.Add(newAdvert); > } > > but I want to not have to check if it already exists in the DB if > possible by just calling pw.PreRollAdverts.Add(advert); > > and letting nhibernate figure out that the advert which I'm attempting > to add to the parents collection is itself already in the DB so dont > add it again just update the association column or table. I have > implemented equals in my advert object but it's does not seem to be > getting hit. It looks like the following: > > //implemented so NH will not attempt to insert new 'duplicate' ads > public override bool Equals(object obj) > { > if (obj == null) > return false; > > RollAdvert ra = obj as RollAdvert; > if (ra == null) > return false; > > //adverts are equal if there URLs match > return URL == ra.URL; > } > > so do I have to explicity check if something is already in the DB or > call I just do something like pw.PreRollAdverts.Clear() and then add > in everything to the collection. I have cascade-delete-orphan set as > the cascade option if that's important. > > Thanks in advance. > > -- > 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. > > -- 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.
