接着使用复合主键(1)继续：
还是那三张表哟！
Users表(用户信息表)：
UserID char(10) not null primary key,
UserName varchar(50)
Books表（图书信息表）：
BSN char(10) not null primary key,
BookName varchar(50)
BorrowRecord表（图书借还登记表）：
UserID char(10) not null,
BSN char(10) not null,
BorrowDate DateTime not null,
ReturnDate DateTime,
constraint PK_Library primary key (UserID,BSN,BorrowDate)
Users.UserID 对于 BorrowRecord.UserID 是 one-to-many
Books.BSN 对于 BorrowRecord.BSN 是 one-to-many
==============================================================================
Users表
namespace Model2
{
#region User
/// <summary>
/// User object for NHibernate mapped table 'Users'.
/// </summary>
public class User
{
#region Member Variables
protected string _id;
protected string _userName;
protected IList _borrowRecord;
#endregion
#region Constructors
public User() { }
public User( string userName )
{
this._userName = userName;
}
#endregion
#region Public Properties
public virtual string Id
{
get {return _id;}
set
{
if ( value != null && value.Length > 10)
throw new ArgumentOutOfRangeException("Invalid value for Id", value, value.ToString());
_id = value;
}
}
public virtual string UserName
{
get { return _userName; }
set
{
if ( value != null && value.Length > 50)
throw new ArgumentOutOfRangeException("Invalid value for UserName", value, value.ToString());
_userName = value;
}
}
public virtual IList BorrowRecord
{
get
{
if (_borrowRecord == null)
{
_borrowRecord = new ArrayList();
}
return _borrowRecord;
}
set { _borrowRecord = value; }
}
#endregion
}
#endregion
}
==============================================================================
User的xml映射文件(User.hbm.xml)：
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Model2.User, Model2" table="Users">
<id name="Id" type="String" unsaved-value="null">
<column name="UserID" length="10" sql-type="char" not-null="true" unique="true" index="PK_Users"/>
<generator class="assigned" />
</id>
<property name="UserName" type="String">
<column name="UserName" length="50" sql-type="varchar" not-null="false"/>
</property>
<bag name="BorrowRecord" inverse="true" lazy="true" cascade="all-delete-orphan">
<key column="UserID"/>
<one-to-many class="Model2.BorrowRecord, Model2"/>
</bag>
</class>
</hibernate-mapping>
==============================================================================
Books类：
namespace Model2
{
#region Book
/// <summary>
/// Book object for NHibernate mapped table 'Books'.
/// </summary>
public class Book
{
#region Member Variables
protected string _id;
protected string _bookName;
protected IList _borrowRecord;
#endregion
#region Constructors
public Book() { }
public Book( string bookName )
{
this._bookName = bookName;
}
#endregion
#region Public Properties
public virtual string Id
{
get {return _id;}
set
{
if ( value != null && value.Length > 10)
throw new ArgumentOutOfRangeException("Invalid value for Id", value, value.ToString());
_id = value;
}
}
public virtual string BookName
{
get { return _bookName; }
set
{
if ( value != null && value.Length > 50)
throw new ArgumentOutOfRangeException("Invalid value for BookName", value, value.ToString());
_bookName = value;
}
}
public virtual IList BorrowRecord
{
get
{
if (_borrowRecord == null)
{
_borrowRecord = new ArrayList();
}
return _borrowRecord;
}
set { _borrowRecord = value; }
}
#endregion
}
#endregion
}
==============================================================================
Books的xml映射文件(Book.hbm.xml)：
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Model2.Book, Model2" table="Books">
<id name="Id" type="String" unsaved-value="null">
<column name="BSN" length="10" sql-type="char" not-null="true" unique="true" index="PK_Books"/>
<generator class="assigned" />
</id>
<property name="BookName" type="String">
<column name="BookName" length="50" sql-type="varchar" not-null="false"/>
</property>
<bag name="BorrowRecord" inverse="true" lazy="true" cascade="all-delete-orphan">
<key column="BSN"/>
<one-to-many class="Model2.BorrowRecord, Model2"/>
</bag>
</class>
</hibernate-mapping>
==============================================================================
BorrowRecord类：
namespace Model2
{
#region BorrowRecord
/// <summary>
/// BorrowRecord object for NHibernate mapped table 'BorrowRecord'.
/// </summary>
//[Serializable]
public class BorrowRecord
{
#region Member Variables
protected BorrowRecordPK borrowPK;
protected DateTime _returnDate;
#endregion
#region Constructors
public BorrowRecord() { }
public BorrowRecord( DateTime returnDate )
{
this._returnDate = returnDate;
}
#endregion
#region Public Properties
public virtual DateTime ReturnDate
{
get { return _returnDate; }
set { _returnDate = value; }
}
public virtual BorrowRecordPK BorrowPK
{
set
{
borrowPK = value;
}
get
{
return borrowPK;
}
}
#endregion
}
#endregion
}
==============================================================================
BorrowRecord复合主键类：
namespace Model2
{
[Serializable]
public class BorrowRecordPK
{
protected Book _book;
protected User _user;
public BorrowRecordPK()
{
}
public virtual User User
{
set { _user = value; }
get { return _user; }
}
public virtual Book Book
{
set { _book = value; }
get { return _book; }
}
private DateTime borrowDate;
public virtual DateTime BorrowDate
{
set
{
borrowDate = value;
}
get
{
return borrowDate;
}
}
/// <summary>
/// 判断两个对象是否相同，这个方法需要重写
/// </summary>
/// <param name="obj">进行比较的对象</param>
/// <returns>真true或假false</returns>
public override bool Equals(object obj)
{
if (obj is BorrowRecordPK)
{
BorrowRecordPK second = obj as BorrowRecordPK;
if (this._user == second._user
&& this._book == second._book
&& this.BorrowDate == second.BorrowDate)
{
return true;
}
else return false;
}
return false;
}
public override int GetHashCode()
{
return base.GetHashCode();
}
}
}
==============================================================================
BorrowRecord的xml映射文件(BorrowRecord.hbm.xml)：
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Model2.BorrowRecord, Model2" table="BorrowRecord">
<composite-id name="BorrowPK" class="Model2.BorrowRecordPK, Model2">
<key-many-to-one name="User" class="Model2.User, Model2" column="UserID" />
<key-many-to-one name="Book" class="Model2.Book, Model2" column="BSN" />
<key-property name="BorrowDate" />
</composite-id>
<property name="ReturnDate" type="DateTime">
<column name="ReturnDate" length="8" sql-type="datetime" not-null="false"/>
</property>
</class>
</hibernate-mapping>
主要要注意的是：
1、使用了复合主键类要重写Equals()和GetHashCode()方法。
2、要将该复合类Serializable.
3、xml映射文件要设置为嵌入的资源。