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Is there a way to write something like this:

public class Item
{
    public DateTime Start { get; set; }
    public DateTime Finish{ get; set; }
}

Sessin.Query<Item>.Where( x => x.Start.AddHours( 3 ) > x.Finish );

Now i get an exception

[NotSupportedException: System.DateTime AddHours (Double)]

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2 answers

LINQ. , NHibernate , DateTime.AddHours(double hours). HQL ? . HQL AddHours. . NHibernate SQL SQL. , , RegisterFunctions. . NHibernate, LINQ. "" DateTime.AddHours(double hours) hql. NHibernate . linq-to-hql .

, NHibernate 3.3

( MsSql2008Dialect)

    public class EnhancedMsSql2008Dialect : MsSql2008Dialect
    {
        protected override void RegisterFunctions() {
            base.RegisterFunctions();
            RegisterFunction("add_hours", new SQLFunctionTemplate(NHibernateUtil.DateTime, "dateadd(hour, ?1, ?2)"));
        }
    }

LINQ-to-HQL, , AddHours

    using NHibernate.Linq.Functions;
    using NHibernate.Linq;
    using NHibernate.Hql.Ast;

    public class DateTimeMethodsHqlGenerator : BaseHqlGeneratorForMethod
    {
        public DateTimeMethodsHqlGenerator() {
            SupportedMethods = new[] {
                ReflectionHelper.GetMethodDefinition((DateTime x) => x.AddHours(1))
            };
        }

        public override HqlTreeNode BuildHql(System.Reflection.MethodInfo method, System.Linq.Expressions.Expression targetObject, System.Collections.ObjectModel.ReadOnlyCollection arguments, HqlTreeBuilder treeBuilder, NHibernate.Linq.Visitors.IHqlExpressionVisitor visitor) {
            return treeBuilder.MethodCall("add_hours", visitor.Visit(arguments[0]).AsExpression(), visitor.Visit(targetObject).AsExpression());
        }
    }

LINQ-to-HQL

    public class EnhancedLinqToHqlGeneratorsRegistry : DefaultLinqToHqlGeneratorsRegistry
    {
        public EnhancedLinqToHqlGeneratorsRegistry() : base() {
            //
            RegisterGenerator(ReflectionHelper.GetMethodDefinition((DateTime x) => x.AddHours(1)), new DateTimeMethodsHqlGenerator());
        }
    }


    cfg.DataBaseIntegration(c => {
        c.Dialect<EnhancedMsSql2008Dialect>();
    });
    cfg.LinqToHqlGeneratorsRegistry<EnhancedLinqToHqlGeneratorsRegistry>();
+7

NH 3.3 Loquacious, - .

LinqToHqlGeneratorsRegistry : -

        var configure = new Configuration()
            .DataBaseIntegration(x => {
                x.Dialect<CustomDialect>();
                x.ConnectionStringName = "db";
             })
            .LinqToHqlGeneratorsRegistry<MyLinqtoHqlGeneratorsRegistry()
            .CurrentSessionContext<WebSessionContext>();

: -

public class MyLinqtoHqlGeneratorsRegistry : DefaultLinqToHqlGeneratorsRegistry
{
    public MyLinqtoHqlGeneratorsRegistry()
    {
        this.Merge(new AddHoursGenerator());
    }
}

public class AddHoursGenerator : BaseHqlGeneratorForMethod
{
    public AddHoursGenerator()
    {
        SupportedMethods = new[] {
        ReflectionHelper.GetMethodDefinition<DateTime?>(d =>      
                d.Value.AddHours((double)0))
          };
    }

    public override HqlTreeNode BuildHql(MethodInfo method,
        System.Linq.Expressions.Expression targetObject,
        ReadOnlyCollection<System.Linq.Expressions.Expression> arguments,
        HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
    {
        return treeBuilder.MethodCall("AddHours",
                visitor.Visit(targetObject).AsExpression(),
                visitor.Visit(arguments[0]).AsExpression()
            );
    }
}

public class CustomDialect : MsSql2008Dialect
{
    public CustomDialect()
    {
        RegisterFunction(
             "AddHours",
             new SQLFunctionTemplate(
                  NHibernateUtil.DateTime,
                  "dateadd(hh,?2,?1)"
                  )
             );
    }
}

fabio.

: -

Session.Query<Item>.Where( x => x.Start.AddHours( 3 ) > x.Finish );

3.2, public override HqlTreeNode BuildHql(..) ...

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