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>(); 

Baht

What is your database server and default database collation? – Apodaca

Answer 1

In QueryOver you can use following:

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

Squalor

how could you explain the fact that the CreateCriteria works properly? – Baht

By default SQL server makes case insensitive strings comparison, but can be configured differently. ICriteria doesn't add anything in SQL it will just generate where Login = 'username'. Can't say it about QueryOver. You should check what SQL it produces. Insensitive like will cause ToLower call in SQL – Squalor

I just ran into a problem with solution. In this case, the username had an underscore character in it, and Oracle treats the underscore as a wildcard. So I had both bob.marley and bob_marley in the database and the SingleOrDefault crashed. – Natch

Careful - allowing user input to be a LIKE expression is very prone to being a big security hole. NB, the OP did not ask for a Like, but for equality (which would make sense) – Rivy

You should probably read question carefully before putting "valuable" comments – Squalor

This logic is not the same as the question requires. Be careful with that "like". – Counterinsurgency

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)

Haemostat

The exact syntax above didn't work. Here is what worked for me: query.Where(Restrictions.Eq(nameof(MyClass.Property), value).IgnoreCase()); – Unrelenting

Answer 3

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

Apodaca

Darius, I don't know if it is a problem with the collection cause CreateCriteria works properly:Domain.User User = Session.CreateCriteria<Domain.User>() .Add(Expression.Eq("Login", "username")) .UniqueResult<Domain.User>(); – Baht

@Baht - If your collation is case insensitive you don't have to specify case sensitivity in your query (all queries will be case insensitive by default). – Apodaca

You're right Darius but changing collation in Oracle is not as easy as in Sql Server and I can't do it cause I am not the owner of the DB. – Baht

np ;) - as I wrote 'If you can change database...' – Apodaca

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)

Counterinsurgency

Answer 5

NH 3.0 has a linq provider so you can use

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

Handball

I've already tried that. It doesn't work. I get this error: {"Unrecognised method call in epression x.Login.ToLower()"} . could it be cause I am using oracle? – Baht

@Baht what version nhibernate you have? – Handball

I've checked and the behavior is the same in Sql Server 2008: Unrecognised method call in epression x.Login.ToLower() – Baht

@Baht Confirm not working with QueryOver but working with linq to nhibernate. All i can to recomend you its use linq for nhibernate. its all ok with linq in version 3.0 – Handball

It's strange cause if I create a critiria is case insensitive (and works): Domain.User User = Session.CreateCriteria<Domain.User>() .Add(Expression.Eq("Login", "username")) .UniqueResult<Domain.User>(); – Baht