Please post the relevant SQL in both cases.
On Thu, Jan 15, 2009 at 12:39 PM, Gabriele Tassi
<[email protected]>wrote:
>
> Hello everybody,
>
> this is my first post in this group and I wonder if anybody has
> experienced this same problem.
>
> I'm working on a NHibernate-based project and I wanted to play a
> little with Linq to NHibernate, from NHibernate Contrib.
>
> So I happily integrated it in my system and turned some existing Hql
> queries into Linq expressions.
> Just as a simplified example: let's say that I had this function...
>
> IEnumerable<User> GetUsers(ISession Session, long SiteId)
> {
> return Session.CreateQuery(@"
> select User
> from User User
> where User.Site.Id = :SiteId
> ")
> .SetInt64(":SiteId")
> .Enumerable<User>();
> }
>
> What I did is to turn it in this form:
>
> IEnumerable<User> GetUsers(ISession Session, long SiteId)
> {
> return
> from User in Session.Linq<User>()
> where User.Site.Id = SiteId
> select User;
> }
>
> In order to check that everything was ok, I turned on Sql Profiler to
> examine the generated Sql query.
>
> Here I noticed that query lacked an important optimization that is
> normally present when you create a query using Hql.
>
> In the first case the generated Sql query contains no join between
> User and Site and the expression [UserClient.Site.Id] is replaced
> (roughly) by [USER.SITE_FK].
>
> In the second, sadly, no optimization and a nasty and useless join.
>
> This example is a simplified version of my real case, in which I had 3
> joins completely without purpose!
>
> I went through the code of Linq to NHibernate and I realized what
> maybe you all already know, that is that it is implemented using the
> ICriteria objects. Now, from further tests, it seems to me that it's
> the Criteria system that lacks this optimization: every reference to
> related entities, even just to retrieve the id, lead to a join.
>
> Does anybody of you have thoughts to share about this?
>
> >
>
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