父类的区分值

public class ParentMap : ClassMap<Parent>
{
    this.Id(x => x.Id);
    this.DiscriminateSubClassesOnColumn("Discriminator", "Bar");        
}

public class ChildMap : SubClassMap<Child> // Child : Parent
{
    this.DiscriminatorValue("Foo");
}

方法DiscriminateSubClassesOnColumn的第二个参数是baseClassDescriminator。

这个怎么样 public class ClassMap<T> :

第一次过载

public DiscriminatorPart DiscriminateSubClassesOnColumn<TDiscriminator>(
    string columnName)

第二次过载

/// <summary>
/// Specify that this entity should use a discriminator with it's subclasses.
/// This is a mapping strategy called table-per-inheritance-hierarchy; where all
/// subclasses are stored in the same table, differenciated by a discriminator
/// column value.
/// </summary>
/// <typeparam name="TDiscriminator">Type of the discriminator column</typeparam>
/// <param name="columnName">Discriminator column name</param>
/// <param name="baseClassDiscriminator">Default discriminator value</param>
public DiscriminatorPart DiscriminateSubClassesOnColumn<TDiscriminator>(
    string columnName, TDiscriminator baseClassDiscriminator)

换句话说,使用第二个重载并提供默认值。。。