Question

I have the following (simplified)

public enum Level
{
    Bronze,
    Silver,
    Gold
}

public class Member
{
    public virtual Level MembershipLevel { get; set; }
}

public class MemberMap : ClassMap<Member>
{
    Map(x => x.MembershipLevel);
}

This creates a table with a column called MembershipLevel with the value as the Enum string value.

What I want is for the entire Enum to be created as a lookup table, with the Member table referencing this with the integer value as the FK.

Also, I want to do this without altering my model.

Answer 1

To map an enum property as an int column, use method CustomType.

public class MemberMap : ClassMap<Member>
{
    Map( x => x.MembershipLevel ).CustomType<int>();
}

In order to keep the enum and lookup table in sync, I would add the lookup table and data to your sql scripts. An integration test can verify that the enum and lookup table values are the same.

If you wanted SchemaExport to create this table, add a class and mapping for it.

public class MembershipLevel
{
    public virtual int Id { get; set; }
    public virtual string Code { get; set; }
}

public class MembershipLevelMap : ClassMap<MembershipLevel>
{
    Id( x => x.Id );
    Map( x => x.Code );
}

If you are creating the table with SchemaExport, you will need to populate it as well:

foreach (Level l in Enum.GetValues( typeof( Level ))) {
    session.Save( new MembershipLevel{ Id = (int) l, Code = l.ToString() });
}