Nhibernate + QueryOver: filter with Where ignoring sensitive

Question

I am trying to build a simple query in nHibernate with QueryOver but I want it to convert everything lower-case or ignore sensitive:

Domain.User User = Session.QueryOver<Domain.User>()
       .Where(x=>x.Login=="username")
       .SingleOrDefault();

How can I achieve this?

UPDATE:

Someone suggested that the problem could be with the colletion of the DB but I've never had any kind of problem with that and this script works:

Domain.User User = Session
    .CreateCriteria<Domain.User>() 
    .Add(Expression.Eq("Login", "username")) 
    .UniqueResult<Domain.User>(); 

Answer 1

In QueryOver you can use following:

Domain.User User = Session.QueryOver<Domain.User>()
       .WhereRestrictionOn(x=>x.Login).IsInsensitiveLike("username")
       .SingleOrDefault();

Answer 2

my workaround for this is using a expression.eq combined with a projection, so a case insensitive equals without any magic strings can be done with queryover

query.Where(Expression.Eq(Projections.Property(Of MyType)
                (Function(x) x.Name), "something").IgnoreCase)

Answer 3

Better way is to change collation of your database to case insensitive one. If you can change database.

Answer 4

public static class QueryOverExtension
{
    /// <summary>
    /// This method is used in cases where the root type is required
    /// Example: .WhereEqualInsensitive(t => t.Property, stringValue)
    /// </summary>
    public static IQueryOver<T, TU> WhereEqualInsensitive<T, TU>(this IQueryOver<T, TU> queryOver, Expression<Func<T, object>> path, string value)
    {
        return queryOver.Where(Restrictions.Eq(Projections.SqlFunction("upper", NHibernateUtil.String, Projections.Property(path)), value.ToUpper()));
    }

    /// <summary>
    /// This method is used in cases where the root type is NOT required
    /// Example: .WhereEqualInsensitive(() => addressAlias.DefaultEmail, contactEmailAddress)
    /// </summary>
    public static IQueryOver<T, TU> WhereEqualInsensitive<T,TU>(this IQueryOver<T, TU> queryOver, Expression<Func<object>> path, string value)
    {
        return queryOver.Where(Restrictions.Eq(Projections.SqlFunction("upper", NHibernateUtil.String, Projections.Property(path)), value.ToUpper()));
    }
}

Usages:

Session.QueryOver<DTO>()
           .WhereEqualInsensitive(t => t.Property, value)

ChildDTO childAlias = null;
Session.QueryOver<DTO>()
           .JoinAlias(t => t.ChildDTO, () => childAlias)
           .WhereEqualInsensitive(() => myAlias.Property, value)

Answer 5

NH 3.0 has a linq provider so you can use

Session.Query<Domain.User>()
           .Where(x=>x.Login.ToLower() =="username")
           .SingleOrDefault();