How best to inject value translation into an NHibernate property? - nhibernate

Question

I have a model like this:
public class Order
{
public virtual int OrderType { get; set; }
}
(lots of other properties omitted of course) which maps directly to an int type in the DB.
The thing is, the numeric order type is meaningless to my application. There are single-letter codes that the user sees which denote the order type. So, I could do something like this:
public class Order
{
public virtual int OrderTypeIgnored { get; set; }
public virtual char OrderType
{
get
{
return translateForward(OrderTypeIgnored);
}
set(char val)
{
OrderTypeIgnored = translateBackward(val);
}
}
}
(lots of air code/pseudocode there, I'm relatively new to C#) and just map the OrderTypeIgnored property. But is there a cleaner way to do this? Perhaps somehow overriding the getter and setter on the mapped property itself?
A few notes: The values are static enough that embedding the translation in the code is not a problem. No, there's no LOV table, and no, I don't have control over the database structure.
Sorry if there are answers for this, but searching for things like "mapping" and "translation" don't really get me the results I'm looking for, obviously.

Answer 1

You could create a public char property that uses a private int field and only map the field.
Model:
public class Order
{
private int _orderType;
public virtual char OrderType
{
get
{
return TranslateForward(_orderType);
}
set
{
_orderType = TranslateBackward(value);
}
}
}
Mapping:
<property name="_orderType" access="field" />
If you don't want to map the field directly (because you use a compile-safe mapping) you can map the public property using the access strategy "field", a naming strategy like "camelcase-underscore" and explicitly specify the "Int32" type.

Answer 2

you can always use enums for this kind of situation.
You can define it like this:
namespace MyApp.Domain
{
using System.ComponentModel;
public enum OrderType : short
{
[Description("Order Suspended")]
Suspended = 1,
[Description("Order Delivered")]
Delivered = 2,
[Description("Order New")]
Inserted = 3
}
}
and map it this way:
<property name="Type" type="MyApp.Domain.OrderType, MyApp.Domain" >
<column name="Type" not-null="true"/>
</property>
so you can write your QueryOver in a simple way like this:
var orders = this.Session.QueryOver<MyApp.Domain.Orders>()
.Where(x => x.Type == MyApp.Domain.OrderType.Inserted)
.List();