How does one make NHibernate stop using nvarchar(4000) for insert parameter strings?

Question

I need to optimize a query that is being produced by a save (insert query) on a domain entity. I\'ve configured NHibernate using Fluent NHibernate.

Here\'s the query ge

Answer 1

This issue can cause a huge performance problem in queries if it forces SQL Server to perform a table scan instead of using an index. We use varchar throughout our database so I created a convention to set the type globally:

/// 

/// Convert all string properties to AnsiString (varchar). This does not work with SQL CE.
/// 
public class AnsiStringConvention : IPropertyConventionAcceptance, IPropertyConvention
{
    public void Accept(IAcceptanceCriteria criteria)
    {
        criteria.Expect(x => x.Property.PropertyType.Equals(typeof(string)));
    }

    public void Apply(IPropertyInstance instance)
    {
        instance.CustomType("AnsiString");
    }

}