NHibernate and operator overloading

Question

public class Version
{
    public byte Major { get; set; }
    public byte Minor { get; set; }
    public short Build { get; set; }
    public int Revision { get; set; }

    private long NumVersion
    {
        //get {}
        //set {}
        //Some logic that make Int64 number that represents this verion
    }
}

Suppose I want to be able to write queries like

Where<Product>(t=>t.Version > new Version(1,2,0,0))

In Product table I store only Int64 NumVersion field, so Version property is mapped as component, and currently I query it like Where<Product>(t=>t.Version.NumVersion > new Version(1,2,0,0).NumVersion)

In C# I can 1. Overload comparison operators, 2. Make it implicitly casted to long like:

public static implicit operator long(Version v)
{
    return v.NumVersion;
}

This will allow me to compare Version objects, but how to make NHibernate understand this and generate proper SQL ?

Answer 1

It is impossible. You will either have to explicitly write comparisons for each Version component or filter on the client side.

Answer 2

Maybe:

class p
{
    private p() { }

    public static p Version { get { return new p(); } }

    public static Expression<Func<Product, bool>> operator >(p left, Version version)
    {
        return product => product.Version.NumVersion > version.NumVersion;
    }
    ...
}


Where<Product>(p.Version > new Version(1,2,0,0))