NHibernate follows the SQL model. In general, the behavior is that foo =
null is always false.It does so by delegating to the DB, but we are
explicitly providing IsNull and IsNotNull for the purpose of null
comparisions.
On Thu, Oct 2, 2008 at 6:22 PM, Tapio Kulmala <[EMAIL PROTECTED]>wrote:
>
> Hi Thomas!
>
> This is an interesting issue. You probably have ansi_nulls off in your
> database. That setting changes dramatically the behavior of null-
> comparisons. You can test it easily in northwind database
>
> set ansi_nulls on
> select * from orders where not shippeddate = null
> select * from orders where not shippeddate is null
>
> set ansi_nulls off
> select * from orders where not shippeddate = null
> select * from orders where not shippeddate is null
>
> Oren, Fabio, anybody....
>
> What's the recommended setting with NHibernate? Does NHibernate create
> ANSI compatible null checks / SQL?
>
> Tapio
>
>
>
> On Oct 1, 12:52 pm, Thomas Koch <[EMAIL PROTECTED]> wrote:
> > Hi - I am using NH 2.0 against SQL Server 2005.
> >
> > I am comparing two properties from different classes using the
> > Restrictions.NotEqProperty method of the criteria API and everything
> > is working like a charm. That all changed when I suddenly encountered
> > null values.
> >
> > A fragment of my query:
> >
> > Disjunction disjunction = new Disjunction();
> > disjunction.
> > .Add(Restrictions.NotEqProperty("f.Owner", "s.Owner"))
> > .Add(Restrictions.NotEqProperty("f.Name", "s.Name")) ...
> >
> > This results in the following SQL fragment:
> > ...
> > not this_0_.Owner = this_.Owner or
> > not this_0_.Name = this_.Name or
> > ...
> >
> > What happens is that when s.Owner for instance is NULL and f.Owner is
> > not null then "this_0_.Owner = this_.Owner" still evaluates to true on
> > the SQL Server.
> >
> > My instincts now tell med that comparing NULLs with non-NULL values is
> > something that is vendor specific.
> >
> > But looking at the Restrictions.NotEqProperty I would have expected it
> > to handle this issue.
> >
> > Can anyone suggest an alternative?
> >
> > Kind regards,
> > Thomas
> >
>
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