How to map enum as string in database

Question

My table:

create table MyTable (
    Id int identity(1,1) not null,
    MyStatus char(2) not null
)
insert into MyTable(MyStatus) select 'A'

Class and enum:

public class MyTable
{
    public virtual int Id { get; set; }
    public virtual MyTableStatus MyStatus { get; set; }
}

public enum MyTableStatus
{
    A,
    B
}

Mapping:

public MyTableMap()
{
    Id(x => x.Id);
    Map(x => x.MyStatus);
}

When I execute the following test, I get System.FormatException : Input string was not in a correct format...

[Test]
public void Blah()
{
    MyTable myTable = Session.Get<MyTable>(1);
    Assert.That(myTable.MyStatus, Is.EqualTo(MyTableStatus.A));
}

What is the right way to map an enum to it's string representation in the database?

Edit - I am writing my application on an existing database, which I cannot modify easily because it is used by other applications also. So some fields in the database (which I would like to represent as enums in my application) are of type int and some of type char(2).

Answer 1

You need to create a custom IUserType to convert an enum to its string representation and back. There's a good example in C# here and an example in VB.NET for working with enums here (scroll down to implementing IUserType).