通過進一步學習nhibernate基礎知識，在實現單表CRUD的基礎上，實現兩表之間one-to-many的關系.

2.     開發環境+必要準備

開發環境: windows 2003,Visual studio .Net 2005,Sql server 2005 developer edition

必要準備: 學習上篇文章單表操作   

3． 對上篇文章中部分解釋

 1）在User.hbm.xml中class節點中有一個lazy的屬性，這個屬性用于指定是否需要延遲加載（lazy loading），在官方文檔中稱為:lazy fecting.可以說延遲加載是nhibernate最好的特點，因為它可以在父類中透明的加載子類集合，這對于many-to-one的業務邏輯中，真是方便極了。但是有些時候，父類是不需要攜帶子類信息的。這時候如果也加載，無疑對性能是一種損失。在映射文件的class節點中可以通過配置lazy屬性來指定是否支持延遲加載，這就更靈活多了。 

 2) 在User.hbm.xml中generate節點，代表的是主鍵的生成方式，上個例子中的”native”根據底層數據庫的能力選擇identity,hilo,sequence中的一個，比如在MS Sql中，使我們最經常使用的自動增長字段，每次加1. 

3) 在NHibernateHelper.cs中，創建Configuration對象的代碼：new Configuration().Configure(@"E:\myproject\nhibernatestudy\simle1\NHibernateStudy1\NhibernateSample1\hibernate.cfg.xml")；因為我是在單元測試中調試，所以將絕對路徑的配置文件傳遞給構造函數。如果在windows app或者web app可以不用傳遞該參數。 

4． 實現步驟

 1）確定實現的業務需求：用戶工資管理系統

 2) 打開上篇文章中的NHibernateStudy1解決方案。向項目NhibernateSample1添加類Salary;代碼如下

Salary.cs
using System;
using System.Collections.Generic;
using System.Text;

namespace NhibernateSample1
{
    public partial class Salary
    {
        int _id;
        User _user;
        int _year;
        int _month;
        int _envy;
        decimal _money;
        /**//// <summary>
        /// 工資編號
        /// </summary>
        public virtual int Id
        {
            get
            {
                return _id;
            }
            set
            {
                _id = value;
            }
        }
        /**//// <summary>
        /// 雇員
        /// </summary>
        public virtual User Employee
        {
            get
            {
                return _user;
            }
            set
            {
                _user = value;
            }
        }
        /**//// <summary>
        /// 年度
        /// </summary>
        public int Year
        {
            get
            {
                return _year;
            }
            set
            {
                _year = value;
            }
        }
        /**//// <summary>
        /// 月份
        /// </summary>
        public int Month
        {
            get
            {
                return _month;
            }
            set
            {
                _month = value;
            }
        }
        /**//// <summary>
        /// 季度
        /// </summary>
        public int Envy
        {
            get
            {
                return _envy;
            }
            set
            {
                _envy = value;
            }
        }
        /**//// <summary>
        /// 工資
        /// </summary>
        public decimal Money
        {
            get
            {
                return _money;
            }
            set
            {
                _money = value;
            }
        }
    }
}

3) 更改User.cs,在User里面添加SalaryList屬性：

User.cs
 1private System.Collections.IList _salaryList;
 2 /**//// <summary>
 3        /// 工資列表
 4        /// </summary>
 5        public System.Collections.IList SalaryList
 6        {
 7            get
 8            {
 9                return _salaryList;
10            }
11            set
12            {
13                _salaryList = value;
14            }
15        }

4）修改User.hbm.xml，加入bag節點

User.hbm.xml
<bag name="SalaryList" table="Salary" inverse="true" lazy="true" cascade="all">
      <key column="Id"/>
      <one-to-many class="NhibernateSample1.Salary,NhibernateSample1"></one-to-many>
    </bag>

Salary.hbm.xml
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="NhibernateSample1.Salary,NhibernateSample1" table="Salary" lazy="false">
    <id name="Id" column="Id" unsaved-value="0">
      <generator class="native" />
    </id>
    <property name="Year" column="Year" type="Int32" not-null="true"></property>
    <property name="Month"  column="Month"  type="Int32" not-null="true"></property>
    <property name="Envy"  column="Envy"  type="Int32" not-null="true"></property>
    <property name="Money"  column="Money"  type="Decimal" not-null="true"></property>
    <many-to-one name="Employee" column="Uid" not-null="true"></many-to-one>
  </class>
</hibernate-mapping>

）編寫CRUD類

UserSalaryFixure.cs
using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Tool.hbm2ddl;

namespace NhibernateSample1
{
    public  class UserSalaryFixure
    {
        private ISessionFactory _sessions; 
        public void Configure()
        {
            Configuration cfg = GetConfiguration();      
            _sessions = cfg.BuildSessionFactory();
        }
        Configuration GetConfiguration()
        {
            string cfgPath = @"E:\my project\nhibernate study\simle 1\NHibernateStudy1\NhibernateSample1\hibernate.cfg.xml";
            Configuration cfg = new Configuration().Configure(cfgPath);
            return cfg;
        }
        public void ExportTables()
        {
            Configuration cfg = GetConfiguration();           
            new SchemaExport(cfg).Create(true, true);
        }
        public User CreateUser(String name,string pwd)
        {
            User u = new User();
            u.Name = name;
            u.Pwd = pwd;
            u.SalaryList = new ArrayList();

            ISession session = _sessions.OpenSession();

            ITransaction tx = null;

            try
            {
                tx = session.BeginTransaction();
                session.Save(u);
                tx.Commit();
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                throw e;
            }
            finally
            {
                session.Close();
            }

            return u;
        }
        public Salary CreateSalary(User u, int year,int month,int envy,decimal money)
        {
            Salary item = new Salary();
            item.Year = year;
            item.Money = money;
            item.Envy = envy;
            item.Month = month;
            item.Employee = u;
            u.SalaryList.Add(item);
            ISession session = _sessions.OpenSession();
            ITransaction tx = null;

            try
            {
                tx = session.BeginTransaction();
                session.Update(u);
                tx.Commit();
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                throw e;
            }
            finally
            {
                session.Close();
            }
            return item;
        }
        public Salary CreateSalary(int uid,int year, int month, int envy, decimal money)
        {
            Salary item = new Salary();
            item.Year = year;
            item.Money = money;
            item.Envy = envy;
            item.Month = month;
            
            ISession session = _sessions.OpenSession();
            ITransaction tx = null;
            try
            {
                tx = session.BeginTransaction();
                User u = (User)session.Load(typeof(User), uid);
                item.Employee = u;
                u.SalaryList.Add(item);
                tx.Commit();
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                throw e;
            }
            finally
            {
                session.Close();
            }
            return item;
        }
        public Salary GetSalary(int salaryID)
        {
            ISession session = _sessions.OpenSession();
            ITransaction tx = null;
            try
            {
                tx = session.BeginTransaction();
                Salary item = (Salary)session.Load(typeof(Salary),
                    salaryID);               
                tx.Commit();
                return item;
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                return null;
            }
            finally
            {
                session.Close();
            }
            return null;
        }
        public User GetUser(int uid)
        {
            ISession session = _sessions.OpenSession();
            ITransaction tx = null;
            try
            {
                tx = session.BeginTransaction();
                User item = (User)session.Load(typeof(User),
                    uid);
                tx.Commit();
                return item;
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                return null;
            }
            finally
            {
                session.Close();
            }
            return null;
        }
        public void UpdateSalary(int salaryID, decimal money)
        {
            ISession session = _sessions.OpenSession();
            ITransaction tx = null;
            try
            {
                tx = session.BeginTransaction();
                Salary item = (Salary)session.Load(typeof(Salary),
                    salaryID);
                item.Money = money;
                tx.Commit();
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                throw e;
            }
            finally
            {
                session.Close();
            }
        }

        public void Delete(int uid)
        {
            ISession session = _sessions.OpenSession();
            ITransaction tx = null;
            try
            {
                tx = session.BeginTransaction();
                Salary item = session.Load(typeof(Salary), uid) as Salary; ;
                session.Delete(item);
                tx.Commit();
            }
            catch (HibernateException e)
            {
                if (tx != null) tx.Rollback();
                throw e;
            }
            finally
            {
                session.Close();
            }
        }

    }
}

編寫單元測試類：UnitTest1.cs

UnitTest1.cs
using System;
using System.Text;
using System.Collections.Generic;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using NhibernateSample1;

namespace TestProject1
{
    /**//// <summary>
    /// UnitTest1 的摘要說明
    /// </summary>
    [TestClass]
    public class UnitTest1
    {
        public UnitTest1()
        {
            //
            // TODO: 在此處添加構造函數邏輯
            //
        }
        NhibernateSample1.UserSalaryFixure usf = new UserSalaryFixure();
        其他測試屬性#region 其他測試屬性
        //
        // 您可以在編寫測試時使用下列其他屬性:
        //
        // 在運行類中的第一個測試之前使用 ClassInitialize 運行代碼
        // [ClassInitialize()]
        // public static void MyClassInitialize(TestContext testContext) { }
        //
        // 在類中的所有測試都已運行之后使用 ClassCleanup 運行代碼
        // [ClassCleanup()]
        // public static void MyClassCleanup() { }
        //
        // 在運行每個測試之前使用 TestInitialize 運行代碼 
        // [TestInitialize()]
        // public void MyTestInitialize() { }
        //
        // 在運行每個測試之后使用 TestCleanup 運行代碼
        // [TestCleanup()]
        // public void MyTestCleanup() { }
        //
        #endregion

        [TestMethod]
        public void Test1()
        {
            usf.Configure();
            usf.ExportTables();
            User u = usf.CreateUser(Guid.NewGuid().ToString(), "ds");
            Assert.IsTrue(u.Id>0);
            Salary s = usf.CreateSalary(u, 2007, 3, 1, (decimal)8000.00);
            Assert.IsTrue(s.Id > 0);
            Salary s1 = usf.CreateSalary(u.Id, 2007, 3, 1, (decimal)7500);
            Assert.IsTrue(s1.Id>0);
            usf.UpdateSalary(s1.Id, (decimal)6000);
            s1 = usf.GetSalary(s1.Id);
            Assert.IsTrue(s1.Money == (decimal)6000);
            usf.Delete(s1.Id);
            s1 = usf.GetSalary(s1.Id);
            Assert.IsNull(s1);
            User u1 = usf.GetUser(1);
            Assert.IsTrue(u1.SalaryList.Count>0);
        }

    }
}

加載測試元數據，直到Test()通過。