NHibernate3剖析：Mapping篇之ConfORM实战(3):OneToOne语义

怼烎@ 2022-03-28 04:37 134阅读 0赞

***本节内容***

*  系列引入
 *  ConfORM概述
 *  One-to-One语义
 *  结语
 *  参考资料

# 系列引入 #

**NHibernate3剖析系列**分别从Configuration篇、Mapping篇、Session篇、Core篇、Tool篇、Practice篇、Extension篇等方面全面揭示NHibernate3版本内容、特性及其应用，完全基于NHibernte3版本。

*  NHibernate专题：[http://kb.cnblogs.com/zt/nhibernate/][http_kb.cnblogs.com_zt_nhibernate]
 *  NHibernate官方站点：[http://nhforge.org/][http_nhforge.org]
 *  NHibernate参考文档：[http://nhforge.org/doc/nh/en/][http_nhforge.org_doc_nh_en]
 *  获取NHibernate地址：[http://sourceforge.net/projects/nhibernate/files/][http_sourceforge.net_projects_nhibernate_files]

# ConfORM概述 #

在[ConfORM实战(1):概览][ConfORM_1]中，描述了ConfORM简单使用。在[ConfORM实战(2):原理][ConfORM_2]中介绍了ConfORM的基本实现原理。如果你不熟悉ConfORM请查看前几篇文章，你也可以到[http://code.google.com/p/codeconform/][http_code.google.com_p_codeconform]获取ConfORM。

在这之前，我们需要为HbmMapping写AsString()扩展方法：用于输出HbmMapping对象的Mapping，用于学习测试使用，具体代码参考[这里][Link 1]。

在Domain设计中，关联关系有单向关联和双向关联两种，那么一对一我们可以分为单向一对一关联(Unidirectional one-to-one)、双向一对一主键关联(Bidirectional one-to-one (primary key association))、双向一对一外键关联(Bidirectional one-to-one (foreign key association))三种情况。这篇使用ConfORM“映射”这些Domain实例吧。

# One-to-One语义 #

我们使用ObjectRelationalMapper类中的OneToOne方法定义两个对象一对一关系。

## 单向一对一关联(Unidirectional one-to-one) ##

**1.Domain**

设计单向一对一关联Domain实例，Person对象和Address对象，人有一个地址。

public class Person
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public Address Address { get; set; }
    }
    
    public class Address
    {
        public int Id { get; set; }
        public string Street { get; set; }
        public int CivicNumber { get; set; }
    }

**2.ConfORM**

使用ConfORM来配置Domain，使之编译生成我们需要的HbmMapping对象。(注意黑体)

[Test]
    public void UnidirectionalOneToOneMappingDemo()
    {
        //show how work with one-to-one and how ConfORM understands OOP
        var orm = new ObjectRelationalMapper();
        var mapper = new Mapper(orm);
        var entities = new[] { typeof(Person), typeof(Address) };
        //use the definition of table-to-class strategy class by class
        orm.TablePerClass(entities);
        // Defining relations
        orm.OneToOne<Person, Address>();
        // Show the mapping to the console
        var mapping = mapper.CompileMappingFor(entities);
        Console.Write(mapping.AsString());
    }

**3.Mapping**

上面测试输出HbmMapping的映射字符串，如果你使用[ReSharper][]或者[TestDriven.Net][]工具测试，你可以看见下面输出：

[ ![UnidirectionalOneToOneMapping][]][_UnidirectionalOneToOneMapping]

**4.原理**

对于单向一对一关联，实际就是设置IManyToOneMapper，ConfORM会在IPatternsAppliersHolder的ManyToOne和ManyToOnePath集合中匹配对应模式适配器，即匹配UnidirectionalOneToOneUniqueCascadeApplier模式适配器，进行相应操作。

UnidirectionalOneToOneUniqueCascadeApplier：应用IManyToOneMapper.Unique(true)和ManyToOneMapper.Cascade(applyCascade.HasValue?applyCascade.Value : Cascade.All)。

## 双向一对一主键关联(Bidirectional one-to-one (primary key association)) ##

**1.Domain**

设计双向一对一关联Domain实例，Person对象和Address对象，人有一个地址，地址有一个人。

public class Person
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public Address Address { get; set; }
    }
    
    public class Address
    {
        public int Id { get; set; }
        public Person Person { get; set; }
        public string Street { get; set; }
        public int CivicNumber { get; set; }
    }

**2.ConfORM**

使用ConfORM来配置Domain，使之编译生成我们需要的HbmMapping对象。其实这个代码和上面的一样：

[Test]
    public void BidirectionalOneToOneMappingDemo1()
    {
        //show how work with one-to-one and how ConfORM understands OOP
        var orm = new ObjectRelationalMapper();
        var mapper = new Mapper(orm);
        var entities = new[] { typeof(Person), typeof(Address) };
        //use the definition of table-to-class strategy class by class
        orm.TablePerClass(entities);
        // Defining relations
        orm.OneToOne<Person, Address>();
        //or orm.OneToOne<Address,Person>();
        // Show the mapping to the console
        var mapping = mapper.CompileMappingFor(entities);
        Console.Write(mapping.AsString());
    }

**3.Mapping**

测试生成字符串：

[ ![BidirectionalOneToOneMapping][]][_BidirectionalOneToOneMapping]

**4.原理**

对于双向一对一关联，实际就是设置IOneToOneMapper，ConfORM会在IPatternsAppliersHolder的OneToOne和OneToOnePath集合中匹配对应模式适配器，即匹配到以下三个模式适配器，进行相应操作。

BidirectionalPrimaryKeyAssociationMasterOneToOneApplier：应用IOneToOneMapper.Cascade(Cascade.All)

BidirectionalOneToOneAssociationPoidApplier：应用IIdMapper.Generator(Generators.Foreign(BidirectionalOneToOneOrNull(subject.ReflectedType)))

BidirectionalPrimaryKeyAssociationSlaveOneToOneApplier：应用IOneToOneMapper.Constrained(true)

## 双向一对一外键关联(Bidirectional one-to-one (foreign key association)) ##

Domain与双向一对一主键关联(Bidirectional one-to-one (primary key association))相同。

**2.ConfORM**

配置Domain，注意黑体

[Test]
    public void BidirectionalOneToOneMappingDemo2()
    {
        //show how work with one-to-one and how ConfORM understands OOP
        var orm = new ObjectRelationalMapper();
        var mapper = new Mapper(orm);
        var entities = new[] { typeof(Person), typeof(Address) };
        //use the definition of table-to-class strategy class by class
        orm.TablePerClass(entities);
        // Defining relations
        orm.ManyToOne<Person, Address>();
        orm.OneToOne<Address, Person>();
        // Show the mapping to the console
        var mapping = mapper.CompileMappingFor(entities);
        Console.Write(mapping.AsString());
    }

**3.Mapping**

测试生成字符串：

[ ![BidirectionalOneToOneMapping][BidirectionalOneToOneMapping 1]][_BidirectionalOneToOneMapping_BidirectionalOneToOneMapping 1]

**4.原理**

类似的，匹配到以下模式适配器：

BidirectionalForeignKeyAssociationManyToOneApplier：应用IManyToOneMapper.Unique(true)和IManyToOneMapper.Cascade(Cascade.All)

BidirectionalForeignKeyAssociationOneToOneApplier：应用IOneToOneMapper.PropertyReference(GetPropertyOf(manyToOneSideType, oneToOneSideType))

BidirectionalPrimaryKeyAssociationMasterOneToOneApplier：应用IOneToOneMapper..Cascade(Cascade.All)

# 结语 #

这篇文章展示ConfORM的One-to-One语义应用，映射了三种One-to-One映射。

# 参考资料 #

Fabio Maulo：[ConfORM:“Mapping” One-To-One][ConfORM_Mapping_ One-To-One]

[http_kb.cnblogs.com_zt_nhibernate]: http://kb.cnblogs.com/zt/nhibernate/
[http_nhforge.org]: http://nhforge.org/
[http_nhforge.org_doc_nh_en]: http://nhforge.org/doc/nh/en/
[http_sourceforge.net_projects_nhibernate_files]: http://sourceforge.net/projects/nhibernate/files/
[ConfORM_1]: http://www.cnblogs.com/lyj/archive/2010/04/21/inside-nh3-conform-introduction.html
[ConfORM_2]: http://www.cnblogs.com/lyj/archive/2010/09/09/inside-nh3-conform-theory.html
[http_code.google.com_p_codeconform]: http://code.google.com/p/codeconform/
[Link 1]: http://code.google.com/p/codeconform/source/browse/ConfOrm/ConfOrm.UsageExamples/NHibernateMappingsExtensions.cs
[ReSharper]: http://www.jetbrains.com/resharper/
[TestDriven.Net]: http://www.testdriven.net/
[UnidirectionalOneToOneMapping]: /images/20220328/aa00877179ad413d88f5129b318e748e.png
[_UnidirectionalOneToOneMapping]: http://images.cnblogs.com/cnblogs_com/lyj/NH3/ConfOrm-UnidirectionalOneToOneMapping.png
[BidirectionalOneToOneMapping]: /images/20220328/eaba2520d9bb486f90c3f99649a06909.png
[_BidirectionalOneToOneMapping]: http://images.cnblogs.com/cnblogs_com/lyj/NH3/ConfOrm-BidirectionalOneToOneMapping1.png
[BidirectionalOneToOneMapping 1]: https://images.cnblogs.com/cnblogs_com/lyj/NH3/ConfOrm-BidirectionalOneToOneMapping2.png
[_BidirectionalOneToOneMapping_BidirectionalOneToOneMapping 1]: /images/20220328/62397fdc09f848ae84d3327608a4cbdc.png
[ConfORM_Mapping_ One-To-One]: http://fabiomaulo.blogspot.com/2010/03/conform-mapping-one-to-one.html