C# 如何进行流畅的nhibernate一对一映射？

我是如何做到这一点的我正在尝试做一对一的映射

public class Setting
{
    public virtual Guid StudentId { get; set; }
    public virtual DateFilters TaskFilterOption { get; set; }
    public virtual string TimeZoneId { get; set; }
    public virtual string TimeZoneName { get; set; }
    public virtual DateTime EndOfTerm { get; set; }
    public virtual Student Student { get; set; }

}

//类图

 public SettingMap()
        {
           /// Id(Reveal.Member<Setting>("StudentId")).GeneratedBy.Foreign("StudentId");
            //Id(x => x.StudentId);
            Map(x => x.TaskFilterOption).Default(DateFilters.All.ToString()).NvarcharWithMaxSize().Not.Nullable();
            Map(x => x.TimeZoneId).NvarcharWithMaxSize().Not.Nullable();
            Map(x => x.TimeZoneName).NvarcharWithMaxSize().Not.Nullable();
            Map(x => x.EndOfTerm).Default("5/21/2011").Not.Nullable();
            HasOne(x => x.Student);
        }

我错过了什么

编辑

public class StudentMap : ClassMap<Student>
{
    public StudentMap()
    {
        Id(x => x.StudentId).GeneratedBy.Guid();
        HasOne(x => x.Setting).PropertyRef("Student").Cascade.All();
    }
}

public class SettingMap : ClassMap<Setting>
{
    public SettingMap()
    {
        Id(x => x.StudentId).GeneratedBy.Guid();
        Map(x => x.TaskFilterOption).Default(DateFilters.All.ToString()).NvarcharWithMaxSize().Not.Nullable();
        Map(x => x.TimeZoneId).NvarcharWithMaxSize().Not.Nullable();
        Map(x => x.TimeZoneName).NvarcharWithMaxSize().Not.Nullable();
        Map(x => x.EndOfTerm).Default("5/21/2011").Not.Nullable();
        References(x => x.Student).Unique();
    }
}

// try 1

      Setting setting = new Setting
                                          {
                                              TimeZoneId = viewModel.SelectedTimeZone, 
                                              TimeZoneName = info.DisplayName, 
                                              EndOfTerm =  DateTime.UtcNow.AddDays(-1),
                                              Student = student
                                          };
     studentRepo.SaveSettings(setting);
     studentRepo.Commit();

// try 2

  Setting setting = new Setting
                                          {
                                              TimeZoneId = viewModel.SelectedTimeZone, 
                                              TimeZoneName = info.DisplayName, 
                                              EndOfTerm =  DateTime.UtcNow.AddDays(-1),
                                              Student = student
                                          };

student.Setting = setting
studentRepo.CreateStudent(student);
studentRepo.Commit();

---

首先，将关系的一侧定义为Inverse（），否则数据库中会有一个冗余列，这可能会导致问题

---

如果这不起作用，请输出NHibernate生成的SQL语句（使用ShowSql或通过log4net），并尝试了解违反外键约束的原因（或将其与SQL一起发布在此处，并且不要忘记SQL语句后面出现的绑定变量的值）.

您不应该在Sesstings类中定义StudentId。Sessting类已经有了它（从

---

公共虚拟学生学生{get；set；}

）。可能应该是SesstingId，您也应该映射Id字段（您必须定义/映射主键）。

在NH中，有两种基本方法可以映射双向一对一关联。让我们假设这些类如下所示：

public class Setting
{
    public virtual Guid Id { get; set; }
    public virtual Student Student { get; set; }
}

public class Student
{
    public virtual Guid Id { get; set; }
    public virtual Setting Setting { get; set; }
}

Setting类是关联中的主节点（“聚合根节点”）。这是很不寻常的，但它取决于问题领域

主键关联

public SettingMap()
{
    Id(x => x.Id).GeneratedBy.Guid();
    HasOne(x => x.Student).Cascade.All();
}

public StudentMap()
{
    Id(x => x.Id).GeneratedBy.Foreign("Setting");
    HasOne(x => x.Setting).Constrained();
}

public SettingMap()
{
    Id(x => x.Id).GeneratedBy.Guid();
    References(x => x.Student).Unique().Cascade.All();
}

public StudentMap()
{
    Id(x => x.Id).GeneratedBy.Guid();
    HasOne(x => x.Setting).Cascade.All().PropertyRef("Student");
}

并应存储一个新的设置实例：

        var setting = new Setting();

        setting.Student = new Student();
        setting.Student.Name = "student1";
        setting.Student.Setting = setting;
        setting.Name = "setting1";

        session.Save(setting);

外键关联

public SettingMap()
{
    Id(x => x.Id).GeneratedBy.Guid();
    HasOne(x => x.Student).Cascade.All();
}

public StudentMap()
{
    Id(x => x.Id).GeneratedBy.Foreign("Setting");
    HasOne(x => x.Setting).Constrained();
}

public SettingMap()
{
    Id(x => x.Id).GeneratedBy.Guid();
    References(x => x.Student).Unique().Cascade.All();
}

public StudentMap()
{
    Id(x => x.Id).GeneratedBy.Guid();
    HasOne(x => x.Setting).Cascade.All().PropertyRef("Student");
}

主键关联与您的解决方案非常接近。只有在绝对确定关联始终为一对一时，才应使用主键关联。请注意，NH中的一对一不支持AllDeleteOrphan级联

编辑：有关详细信息，请参阅：

---

这里是一个完整的外键关联示例

using System;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using NHibernate;
using FluentNHibernate.Mapping;

namespace NhOneToOne
{
    public class Program
    {
        static void Main(string[] args)
        {
            try
            {

                var sessionFactory = Fluently.Configure()
                                             .Database(
                                                    MsSqlConfiguration.MsSql2005
                                                                      .ConnectionString(@"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=NHTest;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False")
                                                                      .ShowSql()
                                              )
                                             .Mappings(m => m
                                             .FluentMappings.AddFromAssemblyOf<Program>())
                                             .BuildSessionFactory();

                ISession session = sessionFactory.OpenSession();


                Parent parent = new Parent();
                parent.Name = "test";
                Child child = new Child();
                child.Parent = parent;
                parent.Child = child;
                session.Save(parent);
                session.Save(child);

                int id = parent.Id;
                session.Clear();
                parent = session.Get<Parent>(id);
                child = parent.Child;


            }
            catch (Exception e)
            {
                Console.Write(e.Message);
            }
        }

    }

    public class Child
    {
        public virtual string Name { get; set; }
        public virtual int Id { get; set; }

        public virtual Parent Parent { get; set; }
    }

    public class Parent
    {
        public virtual string Name { get; set; }
        public virtual int Id { get; set; }

        public virtual Child Child { get; set; }

    }

    public class ChildMap : ClassMap<Child>
    {
        public ChildMap()
        {
            Table("ChildTable");
            Id(x => x.Id).GeneratedBy.Native();
            Map(x => x.Name);

            References(x => x.Parent).Column("IdParent");

        }
    }

    public class ParentMap : ClassMap<Parent>
    {
        public ParentMap()
        {
            Table("ParentTable");
            Id(x => x.Id).GeneratedBy.Native();
            Map(x => x.Name);

            HasOne(x => x.Child).PropertyRef(nameof(Child.Parent));
        }

    }
}

---

如果我从设置中删除StudentId，那么nhibernate将崩溃，至于PKHmm，这很奇怪。我从未见过这样的例外。它有内部异常吗？是否使用侦听器或拦截器？问题可能是在设置类中有两个属性映射到一列：Student reference和StudentId property。请参阅：。我刚刚创建了一个示例项目，其中“表A”有一个主键，“表B”有一个主键，该主键也是“表A”的外键。在这种情况下，外键关联非常有效。需要记住的重要一点是，“表B”映射需要分别映射主键值和HasOne关联？

using System;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using NHibernate;
using FluentNHibernate.Mapping;

namespace NhOneToOne
{
    public class Program
    {
        static void Main(string[] args)
        {
            try
            {

                var sessionFactory = Fluently.Configure()
                                             .Database(
                                                    MsSqlConfiguration.MsSql2005
                                                                      .ConnectionString(@"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=NHTest;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False")
                                                                      .ShowSql()
                                              )
                                             .Mappings(m => m
                                             .FluentMappings.AddFromAssemblyOf<Program>())
                                             .BuildSessionFactory();

                ISession session = sessionFactory.OpenSession();


                Parent parent = new Parent();
                parent.Name = "test";
                Child child = new Child();
                child.Parent = parent;
                parent.Child = child;
                session.Save(parent);
                session.Save(child);

                int id = parent.Id;
                session.Clear();
                parent = session.Get<Parent>(id);
                child = parent.Child;


            }
            catch (Exception e)
            {
                Console.Write(e.Message);
            }
        }

    }

    public class Child
    {
        public virtual string Name { get; set; }
        public virtual int Id { get; set; }

        public virtual Parent Parent { get; set; }
    }

    public class Parent
    {
        public virtual string Name { get; set; }
        public virtual int Id { get; set; }

        public virtual Child Child { get; set; }

    }

    public class ChildMap : ClassMap<Child>
    {
        public ChildMap()
        {
            Table("ChildTable");
            Id(x => x.Id).GeneratedBy.Native();
            Map(x => x.Name);

            References(x => x.Parent).Column("IdParent");

        }
    }

    public class ParentMap : ClassMap<Parent>
    {
        public ParentMap()
        {
            Table("ParentTable");
            Id(x => x.Id).GeneratedBy.Native();
            Map(x => x.Name);

            HasOne(x => x.Child).PropertyRef(nameof(Child.Parent));
        }

    }
}

CREATE TABLE [dbo].[ParentTable] (
    [Id]   INT           IDENTITY (1, 1) NOT NULL,
    [Name] VARCHAR (MAX) NULL
);
CREATE TABLE [dbo].[ChildTable] (
    [Id]       INT          IDENTITY (1, 1) NOT NULL,
    [IdParent] INT          NOT NULL,
    [Name]     VARCHAR (50) NULL
);
ALTER TABLE [dbo].[ChildTable]
    ADD CONSTRAINT [FK_ChildTable_ToTable] FOREIGN KEY ([IdParent]) REFERENCES [dbo].[ParentTable] ([Id]);