NHibernate3剖析：Mapping篇之ConfORM實戰(3):OneToOne語義

作者: 李永京來源: 博客園發布時間: 2010-09-19 23:24 閱讀: 1094 次推薦: 0 原文鏈接 [收藏]

　　ConfORM概述

　　在ConfORM實戰(1):概覽中，描述了ConfORM簡單使用。在ConfORM實戰(2):原理中介紹了ConfORM的基本實現原理。如果你不熟悉ConfORM請查看前幾篇文章，你也可以到http://code.google.com/p/codeconform/獲取ConfORM。

　　在這之前，我們需要為HbmMapping寫AsString()擴展方法：用于輸出HbmMapping對象的Mapping，用于學習測試使用，具體代碼參考這里。

　　在Domain設計中，關聯關系有單向關聯和雙向關聯兩種，那么一對一我們可以分為單向一對一關聯(Unidirectional one-to-one)、雙向一對一主鍵關聯(Bidirectional one-to-one (primary key association))、雙向一對一外鍵關聯(Bidirectional one-to-one (foreign key association))三種情況。這篇使用ConfORM“映射”這些Domain實例吧。

　　One-to-One語義

　　我們使用ObjectRelationalMapper類中的OneToOne方法定義兩個對象一對一關系。

　　單向一對一關聯(Unidirectional one-to-one)

　　1.Domain

　　設計單向一對一關聯Domain實例，Person對象和Address對象，人有一個地址。

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來配置Domain，使之編譯生成我們需要的HbmMapping對象。(注意黑體)

[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

　　上面測試輸出HbmMapping的映射字符串，如果你使用ReSharper或者TestDriven.Net工具測試，你可以看見下面輸出：

　　4.原理

　　對于單向一對一關聯，實際就是設置IManyToOneMapper，ConfORM會在IPatternsAppliersHolder的ManyToOne和ManyToOnePath集合中匹配對應模式適配器，即匹配UnidirectionalOneToOneUniqueCascadeApplier模式適配器，進行相應操作。

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

　　雙向一對一主鍵關聯(Bidirectional one-to-one (primary key association))

　　1.Domain

　　設計雙向一對一關聯Domain實例，Person對象和Address對象，人有一個地址，地址有一個人。

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來配置Domain，使之編譯生成我們需要的HbmMapping對象。其實這個代碼和上面的一樣：

[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

　　測試生成字符串：

　　4.原理

　　對于雙向一對一關聯，實際就是設置IOneToOneMapper，ConfORM會在IPatternsAppliersHolder的OneToOne和OneToOnePath集合中匹配對應模式適配器，即匹配到以下三個模式適配器，進行相應操作。

　　BidirectionalPrimaryKeyAssociationMasterOneToOneApplier：應用IOneToOneMapper.Cascade(Cascade.All)

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

　　BidirectionalPrimaryKeyAssociationSlaveOneToOneApplier：應用IOneToOneMapper.Constrained(true)

　　雙向一對一外鍵關聯(Bidirectional one-to-one (foreign key association))

　　Domain與雙向一對一主鍵關聯(Bidirectional one-to-one (primary key association))相同。

　　2.ConfORM

　　配置Domain，注意黑體：

[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());
}