流利的NHibernate中的层次零对一关系

Question

我对 nHibernate 有点陌生，特别流利，我在映射类 A 扩展类 B 的关系时遇到问题，但不能保证给定的 A 也是B。这是迄今为止结构的一个想法（并且可以提出建议）：

public class User
{
    public virtual Guid Id;
    public virtual string UserName;
    public virtual string HashedPassword;
    //...
}

public class Student : User
{
    public virtual Guid UserId;
    public virtual School School;
    public virtual float GPA;
}

public class Teacher : User
{
    public virtual Guid UserId;
    public virtual School School;
    public virtual string ClassName;
}

所以我希望拥有可以使用的 Teacher 和 Student 对象，但我也希望能够跟踪它们以进行成员身份验证（因此是 User 基类）。

所以两个问题：

1. 这是一种合理的方式来做我想做的事吗？

2. 如果是这样，如何使用 Fluent nHibernate 进行映射？

Answer 1

选项 1

public class UserMap : ClassMap<User>
{
    public UserMap()
    {
        Table("Users");

        Id(x => x.Id);

        Map(x => x.Name);
        Map(x => x.HashedPassword);
    }
}
public class StudentMap : SubclassMap<Student>
{
    public StudentMap()
    {
        Table("Students");

        References(x => x.School);
        Map(x => x.GPA);
    }
}
public class TeacherMap : SubclassMap<Teacher>
...

表格

Users (
    Id,        // PK
    Name,
    HashedPassword
)
Students (
    User_Id,        // PK, FK
    School_id,
    Gpa
)

选项 2

public class UserMap : ClassMap<User>
{
    public UserMap()
    {
        Table("Users");
        DiscriminateSubclassesOnColumn("UserType", "user");

        Id(x => x.Id);

        Map(x => x.Name);
        Map(x => x.HashedPassword);
    }
}
public class StudentMap : SubclassMap<Student>
{
    public StudentMap()
    {
        DiscriminatorValue("student");

        References(x => x.School);
        Map(x => x.GPA);
    }
}
public class TeacherMap : SubclassMap<Teacher>
...

表格

Users (
    Id,        // PK
    UserType,
    Name,
    HashedPassword
    School_id,
    Gpa
    Classname
)

选项 3

public abstract class UserMap<TUser> : ClassMap<TUser> where TUser : User
{
    public UserMap()
    {
        Id(x => x.Id);

        Map(x => x.Name);
        Map(x => x.HashedPassword);
    }
}
public class StudentMap : UserMap<Student>
{
    public StudentMap()
    {
        Table("Students");

        References(x => x.School);
        Map(x => x.GPA);
    }
}
public class TeacherMap : UserMap<Teacher>
...

表格

Students (
    Id,        // PK
    Name,
    HashedPassword
    School_id,
    Gpa
)
Teachers (
    Id,        // PK
    Name,
    HashedPassword
    School_id,
    Classname
)