ConfORM概述
在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：
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：
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：
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
