Just to be sure... if NH logs sql statement, is it 100% will reach db? I'm just using SQLite inmemory mode, can't use profiler.
On Fri, Oct 3, 2008 at 7:03 PM, Andrew Melnichuk <[EMAIL PROTECTED] > wrote: > I changed > Assert.That(NHibernateUtil.IsInitialized(c.Customers)); > to > Assert.That(c.Customers.Count == 2); > > and it still hits the db, here is the SQL > > // for root > select country0_.Id as Id0_, country0_.Name as Name0_ from Country > country0_ where (Name='Germany' ) > > // for collection > select customer0_.Id as Id1_, customer0_.Name as Name1_, > customer0_.CountryId as CountryId1_ from Customer customer0_ where > ([EMAIL PROTECTED] )and(customer0_.Name='GermanyCustomer1' ); @p0 = > '1' > > // for collection.count > SELECT customers0_.CountryId as CountryId1_, customers0_.Id as Id1_, > customers0_.Id as Id1_0_, customers0_.Name as Name1_0_, > customers0_.CountryId as CountryId1_0_ FROM Customer customers0_ WHERE > [EMAIL PROTECTED]; @p0 = '1' > > > > On Fri, Oct 3, 2008 at 6:54 PM, Ken Egozi <[EMAIL PROTECTED]> wrote: > >> try to simply access the c.Customers and check (via show-sql or DB >> profiler) that the DB is not being hit, but the customers data is being >> hooked from the session cache. >> >> >> On Fri, Oct 3, 2008 at 6:40 PM, Andrew Melnichuk < >> [EMAIL PROTECTED]> wrote: >> >>> Hi all. >>> >>> I have a complex object graph. There is a root entity which has a set of >>> collections (some of them are pretty big), entities in collections have >>> their own collections etc.. - a kind of tree. I need to fetch this tree with >>> minimum performance hit for database. I have tried 2 options for now: >>> 1st - load root entity, and then navigate through properties to load all >>> child and grandchild collections, ofcourse set fetch="subselect" in mapping >>> file before, to prevent select n+1 problem >>> 2nd - use approach, described here >>> http://blogs.hibernatingrhinos.com/nhibernate/archive/2008/04/06/eager-loading-aggregate-with-many-child-collections.aspx, >>> where different collections load by different queries, but session is smart >>> enough, to merge different result to object graph, initializing different >>> collections. >>> >>> But i can't use 1st approach, because i can't define fetch plan on a >>> global level (number of reasons), and i can't use 2nd approach, because it >>> seems that it works fine for 1st level collection only, selecting deeper >>> level collections will produce cartesian product, which will grow with level >>> of query of collection. >>> >>> What i thought about, is would it be possible to use approach based on >>> several queries, like 2nd approach i mentioned. The difference is i tried to >>> start fetching not from the root entity level, but from the level i have to >>> fetch next, after i already fetched with previous query. For example: >>> >>> [Test] >>> public void Test1() >>> { >>> // load root entity >>> Country c = _session >>> .CreateQuery("from Country where Name = 'Germany'") >>> .List<Country>()[0]; >>> >>> // trying to load 1st level child collection >>> _sess >>> .CreateQuery("from Customer cs where cs.Country = :c") >>> .SetParameter("c", c) >>> .List(); >>> >>> Assert.That(NHibernateUtil.IsInitialized(c.Customers)); // >>> fails >>> } >>> >>> I thought that session will initialize Country.Customers collection, but >>> it is not. >>> Ofcourse i could use eager join for this collection and others at the >>> same level, but as i said this will causes cartesian product for deeper >>> collections. >>> I'm not sure that what i did is valid, maybe it is invalid by design, >>> however it seems that session can initialize customers collection, since it >>> "knows" to which country selected customers belongs. >>> >>> Just wanted to ask, how people solve same problems. >>> >>> -- >>> Best regards, >>> Andrew Melnichuk >>> >>> >>> >> >> >> -- >> Ken Egozi. >> http://www.kenegozi.com/blog >> http://www.musicglue.com >> http://www.castleproject.org >> http://www.gotfriends.co.il >> >> >> >> > > > -- > Best regards, > Andrew Melnichuk > -- Best regards, Andrew Melnichuk --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
