问fluent NHibernate中的层次零对一关系
EN

Stack Overflow用户

提问于 2013-07-18 08:37:19

回答 1查看 325关注 0票数 1

我对nHibernate有点陌生，尤其是流利的，而且在映射类A扩展类B的关系时遇到了困难，但是不能保证给定的A也是B。下面是到目前为止结构看起来的一个概念(并且它可以接受建议)：

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;
}

因此，我希望有可以使用的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(因此成为User基类)。

所以有两个问题：

这是做我想做的事的合理方法吗？
如果是这样的话，如何使用Fluent nHibernate进行映射？

.net

nhibernate

orm

fluent-nhibernate

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回答 1

Stack Overflow用户

回答已采纳

发布于 2013-07-19 11:46:59

备选案文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
)