ConfORM概述
如果你不熟悉ConfORM请查看前几篇文章，你可以到http://code.google.com/p/codeconform/获取ConfORM最新版本。
在Domain设计中经常使用集合，在.Net中的集合有四种：Iesi.Collections.Generic.ISet<T>、System.Collections.Generic.ICollection<T>、System.Collections.Generic.IList<T>、System.Collections.Generic.IDictionary<TKey,TValue>，NHibernate分别使用Set、Bag、List、Map映射来映射这些集合，有关这些集合映射基础可以参考下面四篇文章，手动编写简单的Mapping，从此杜绝啥啥啥生成工具(生成的东西太糟蹋了)：
- NHibernate3剖析：Mapping篇之集合映射基础(1):Set映射
- NHibernate3剖析：Mapping篇之集合映射基础(2):Bag映射
- NHibernate3剖析：Mapping篇之集合映射基础(3):List映射
- NHibernate3剖析：Mapping篇之集合映射基础(4):Map映射
这篇我们使用ConfORM“映射”多对多关联。关联关系有单向关联和双向关联两种，所以分为单向多对多关联(Unidirectional many-to-many)、双向多对多关联(Bidirectional many-to-many)。
Many-To-Many语义
使用ConfORM“映射”多对多关联，无论是单向关联还是双向关联，我们只需要使用ObjectRelationalMapper类中的ManyToMany方法即可(下面示例代码的黑体)。ConfORM会根据Domain解析集合成员进行配置。
[Test]
public void ManyToManyMappingDemo()
{
//show how work with many-to-many 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.ManyToMany<Person, Address>();
// Show the mapping to the console
var mapping = mapper.CompileMappingFor(entities);
Console.Write(mapping.AsString());
}
单向多对多关联(Unidirectional many-to-many)
我们使用各种集合定义Domain：
1.Unidirectional using Set<T>
public class Person
{
private ISet<Address> addresses;
public Person()
{
addresses = new HashedSet<Address>();
}
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<Address> Addresses
{
get { return addresses; }
}
}
public class Address
{
public Guid Id { get; set; }
public string Street { get; set; }
public int CivicNumber { get; set; }
}
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：
注意红色块是关键代码，只是按其要求配置了必需标签，其中access是指访问策略，ConfORM根据Domain定义选择了一个正确的访问策略。
2.Unidirectional using Bag<T>
public class Person
{
private ICollection<Address> addresses;
public Person()
{
addresses = new List<Address>();
}
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<Address> Addresses
{
get { return addresses; }
}
}
Mapping
输出HbmMapping的映射字符串结果：
3.Unidirectional using List<T>
public class Person
{
private IList<Address> addresses;
public Person()
{
addresses = new List<Address>();
}
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<Address> Addresses
{
get { return addresses; }
}
}
Mapping
输出HbmMapping的映射字符串结果：
4.Unidirectional using Map<TK,TV>
public class Person
{
private IDictionary<string, Address> addresses;
public Person()
{
addresses = new Dictionary<string, Address>();
}
public Guid Id { get; set; }
public string Name { get; set; }
public IDictionary<string, Address> Addresses
{
get { return addresses; }
}
}
Mapping
输出HbmMapping的映射字符串结果：
双向多对多关联(Bidirectional many-to-many)
Domain
public class User
{
public Guid Id { get; set; }
public string Name { get; set; }
public ISet<Role> Roles { get; set; }
}
public class Role
{
public Guid Id { get; set; }
public string Name { get; set; }
public ISet<User> Users { get; set; }
}
ConfORM
public void DomainDefinition(ObjectRelationalMapper orm)
{
orm.TablePerClass(new[] { typeof(User), typeof(Role) });
orm.ManyToMany<User, Role>();
}
Mapping
输出HbmMapping的映射字符串结果：
结语
这篇文章展示ConfORM的Many-To-Many语义应用，映射了两种Many-To-Many映射。大家同时也注意到了，上面列名的命名规则感觉有点别扭，这是ConfORM按照默认的模式适配器配置了，我们可以增加自定义模式适配器或者使用通用定制化、特定定制化达到自定义的目的，这些内容接下来的文章中介绍。
参考资料
Fabio Maulo：ConfORM: “Mapping” Many-To-Many
