NHIBernate LINQ BIGINT casting

Question

NHIBernate LINQ BIGINT casting

I'm trying to understand the NHibernate SQL output for this entity:

public class Person
{
    public virtual long Id { get; set; }
    public virtual long Number { get; set; }
}

When I write:

var maxNumber = s.Query<Person>().Max(p => p.Number);

The generated SQL looks like this:

select cast(max(person0_.Number) as BIGINT) as col_0_0_ from Person person0_

Why cast if column Number

bigint

?

I am using NHibernate 3.2, SQL Server 2008 R2, the mapping is defined like this:

<class name="NhMappingTest.Person, NhMappingTest">
      <id name="Id"><generator class="increment" /></id>
      <property name="Number" />
</class>

+3

casting max sql sql-server nhibernate

Groo 15 Mar 12 at 12:53

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1 answer

Diego mijelshon · Accepted Answer · 2012-03-16T03:11:10+0000

It is not necessary. This is an implementation detail:

protected HqlTreeNode VisitNhMax(NhMaxExpression expression)
{
    return _hqlTreeBuilder.Cast(
        _hqlTreeBuilder.Max(
            VisitExpression(expression.Expression).AsExpression()), 
            expression.Type);
}

So the code blinds the result.

NHIBernate LINQ BIGINT casting

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