Thanks Gunnar. I think that's what John Davidson was getting at as well. Could you please be so kind and provide more details on this or any other refrences.
I find that the problem with nhibernate is that you get simple things to work just fine. However, as soon as it gets a bit more complicated you are lost between lots of highly scatered information on the Internet. Any offical books and even the online documentation only show very simple examples. Sorry about the rant but that's why some more feedback from you experts would be very good. Thanks. Christian On Sep 14, 5:00 pm, Gunnar Liljas <[email protected]> wrote: > No, having RelationshipStatementPublication as an entity doesn't harm, but > you're not actually using it anywhere, are you? It seems to be completely > unreferenced. > > Sure, > > select cast(count(*) as INT) from > RelationshipStatementPublicati > ons publicatio21_ where > publicatio21_.StatementId = 22762181 > > ...would be enough, but it's not correct. The LINQ query acts upon > BlaInteractions, and that means that it will and should honor the > referential integrity that the mapping implies. > > If you really want it to query like that, add a mapping of > RelationshipStatementPublication, make a readonly mapping of its statementid > column and query on that. > > /G > > 2011/9/14 csetzkorn <[email protected]> > > > > > > > > > Thanks for the reply. > > > "child of statement" - yes I meant “derives from statement” > > > I don't think having RelationshipStatementPublication as entity > > harms ... or does it? Or maybe that’s the whole problem see sql below? > > > In terms of hydrating ... I said this because nhibernate seem to make > > all these unnecessary joins (to hydrate publications?) just for a > > count. Looking at the original sub query (part of the select > > statement): > > > select cast(count(*) as INT) from > > RelationshipStatementPublications publicatio21_, Publication > > publicatio22_ inner join Statements publicatio22_1_ on > > publicatio22_.StatementId=publicatio22_1_.DBId where > > publicatio21_.StatementId = 22762181 and > > publicatio21_.PublicationId=publicatio22_.StatementId > > > it joins RelationshipStatementPublications to publication and so on > > (Publication also derives from statement by the way). > > > This would be enough: > > > select cast(count(*) as INT) from > > RelationshipStatementPublications publicatio21_ where > > publicatio21_.StatementId = 22762181 > > > On Sep 14, 12:11 pm, Gunnar Liljas <[email protected]> wrote: > > > When you say "child of statement", do you mean that it "derives from > > > statement"? > > > > The RelationshipStatementPublication class (in strict terms, not an > > entity) > > > seems unnecessary now. According to the mapping , it seems you are not > > using > > > it anyway. > > > > Whey you say hydrates, do you really mean that? The initial SQL query you > > > showed does not indicate any hydrating. > > > > /G > > > > 2011/9/14 csetzkorn <[email protected]> > > > > > Ok let me try to explain this again – maybe I was not very clear at > > > > the beginning. Sorry! > > > > > I have a class BlaInteraction which is a child of statement. Each > > > > statement has an IList<Publication>. This relationship is also part of > > > > the domain model to make it future proved: > > > > > public class RelationshipStatementPublication : Entity > > > > { > > > > public virtual Statement Statement { get; set; } > > > > public virtual Publication Publication { get; set; } > > > > } > > > > > In my statement mapping I have: > > > > > mapping.HasManyToMany(x => > > > > x.Publications).Table("RelationshipStatementPublications"); > > > > > My ‘naive’ approach to map a BlaInteraction to a viewmodel and count > > > > the number of publications for each BlaInteraction is this: > > > > return from oi in NHibernateSession.Current.Query<BlaInteraction>() > > > > select new BlaViewModel > > > > { > > > > ... > > > > NoPublications = oi.Publications.Count(), > > > > ... > > > > }; > > > > > This does not scale as hnibernate creates sql code that hydrates each > > > > publication of each (TOP n) BlaInteraction to JUST count the number of > > > > publications. This is what I would like to prevent as removing the > > > > ‘hydration joins’ by hand optimising the sql code scales things. > > > > > Please note that I do not want to use SQL as I am trying to use IQuery > > > > to make use of Telerik's 'Linq-based expression engine' which > > > > generates all the 'stuff' for filtering, paging and sorting. > > > > > Another recent (failed) attempt was this: > > > > > return from oi in NHibernateSession.Current.Query<BlaInteraction>() > > > > select new BlaViewModel > > > > { > > > > ... > > > > //NoPublications = > > > > NHibernateSession.Current.QueryOver<BlaInteraction>().Where(x => > > > > x.Statement.Id == > > > > oi.Id).Select(Projections.RowCount()).SingleOrDefault<int>(), > > > > NoPublications = NHibernateSession.Current.CreateSQLQuery("select > > > > count(distinct PublicationId) from > > > > dbo.RelationshipStatementPublications where StatementId > > > > = :StatementId").SetParameter("StatementId", > > > > oi.Id).UniqueResult<int>(), > > > > ... > > > > }; > > > > > The stuff commented out works but does not make sense. I tried this > > > > due to a recent SO comment. > > > > > Thanks. > > > > > Christian > > > > > On Sep 14, 11:08 am, Gunnar Liljas <[email protected]> wrote: > > > > > 1. The join is correct. You ask for the number of publications > > belonging > > > > to > > > > > a specific BlaInteraction. That is what the SQL expresses. > > > > > 2. Is it really important? > > > > > 3. If it is, add the interaction id as a readonly property on the > > > > > publication, and query on that. > > > > > > /G > > > > > > 2011/9/9 csetzkorn <[email protected]> > > > > > > > Hi experts, > > > > > > > Could you please be so kind and have a look at this: > > >http://stackoverflow.com/questions/7359783/prevent-unnecessary-cross-. > > > > .. > > > > > > > Thanks. > > > > > > > Christian > > > > > > > -- > > > > > > 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. > > > -- > > 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. 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