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

2010-09-10 08:45 by 李永京, ... 阅读, ... 评论, 收藏, 编辑

本节内容

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。

ConfORM概述

ConfORM实战(1):概览中,描述了ConfORM简单使用。在ConfORM实战(2):原理中介绍了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/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

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

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

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

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