i want to get the top 1 with nhibernate. i want to get all info in the table and by date and desc. im a newbie to nhibernate so i dont really know how o aproach this.

funny thing tho the most simplest things with sql is the hardest with nhibernate i think.

Both IQuery and ICriteria have a SetMaxResultSize() method. Setting this to 1 results in a TOP(1) query.

im having a real hard time with this, this is how i do. what i want to happend is that i want to get the lunch with todays date. it is a single object no list.
the exception say that i cant cast NHibernate.Impl.CriteriaImpl to [Project Name][LunchDish.

public LunchDish GetTop1()
{
ICriteria crit = _session.CreateCriteria(typeof(LunchDish));
crit.Add(NHibernate.Criterion.Expression.Equals("LunchDate", DateTime.Now)).SetMaxResults(1);
LunchDish result = crit.List<LunchDish>()[0];
return result;
}

Try LunchDish result = crit.UniqueResult<LunchDish>() and if there's only on lunch per day, you don't need SetMaxResult() either.

im getting closer but still i cant compare the LunchDate with todays date. what should i use there?

public LunchDish GetTop1()
{
DateTime date = DateTime.Now;

ICriteria crit = _session.CreateCriteria(typeof(LunchDish));
crit.Add(NHibernate.Criterion.Expression.Equals("LunchDate", date));
LunchDish result = crit.UniqueResult<LunchDish>();
return result;
}

thx for your time

Can you post your mappings ?

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="[Project]" namespace="[Project]">
<class name="[Project]LunchDish" table="LunchDishTbl">
<id name="Id" column="id" type="Int32" unsaved-value="0">
<generator class="native"></generator>
</id>
<property name="Description" column="descr" not-null="false" />
<property name="LunchDate" column="lunch_date" not-null="false" />
<property name="KeyHole" column="keyhole" />
</class>
</hibernate-mapping>

Mapping looks ok. What error do you get ?

System.InvalidOperationException: Sequence contains no elements

there is a row in the table with that date, if its that the exception is?

i changed my code to this.

public LunchDish GetTop1()
{
DateTime date = DateTime.Now;

ICriteria crit = _session.CreateCriteria(typeof(LunchDish));
crit.Add(NHibernate.Criterion.Expression.Eq("LunchDate", date));
LunchDish result = crit.UniqueResult<LunchDish>();
return result;
}

Hmm strange ... sounds more like a basic problem that anything with the query in special.

Does the query work in this way:

ICriteria crit = _session.CreateCriteria(typeof(LunchDish));
IList<LunchDish> result = crit.List<LunchDish>();


Can you post the stacktrace ? Btw. which hibernate version do you use ?

Does the exception only occur when you use SetMaxResults ? If so, then probably you also have to set the first result:

query.SetFirstResult(1);
query.SetMaxResults(1);

i can get all lunches in a list with no problem. i use the nhibernate 2.0 i think it is, the one that is avalible on for download from the site now. i use Jet driver to but that shouldent be any problems because everything else works. i would post the trace but its all in swedish. thing is i changed from 1 to 2 lunches, so i did the ilist and it works.

i tried the setfirst and setmax the other day but it didnt work, i cant remember what the exception was. but then i think the criteria query was wrong.

i am goin to do this top1 agin later today with another part of the application im building so i bet ill be back haha, so please check back on me.

thanks for your time, i really appricate it.