通过进一步学习nhibernate基础知识，在实现单表CRUD的基础上，实现两表之间one-to-many的关系.
2. 开发环境+必要准备
开发环境: windows 2003,Visual studio .Net 2005,Sql server 2005 developer edition
必要准备: 学习上篇文章单表操作
3． 对上篇文章中部分解释
1）在User.hbm.xml中class节点中有一个lazy的属性，这个属性用于指定是否需要延迟加载（lazy loading），在官方文档中称为:lazy fecting.可以说延迟加载是nhibernate最好的特点，因为它可以在父类中透明的加载子类集合，这对于many-to-one的业务逻辑中，真是方便极了。但是有些时候，父类是不需要携带子类信息的。这时候如果也加载，无疑对性能是一种损失。在映射文件的class节点中可以通过配置lazy属性来指定是否支持延迟加载，这就更灵活多了。
2) 在User.hbm.xml中generate节点，代表的是主键的生成方式，上个例子中的”native”根据底层数据库的能力选择identity,hilo,sequence中的一个，比如在MS Sql中，使我们最经常使用的自动增长字段，每次加1.
3) 在NHibernateHelper.cs中，创建Configuration对象的代码：new Configuration().Configure(@"E:\myproject\nhibernatestudy\simle1\NHibernateStudy1\NhibernateSample1\hibernate.cfg.xml")；因为我是在单元测试中调试，所以将绝对路径的配置文件传递给构造函数。如果在windows app或者web app可以不用传递该参数。
4． 实现步骤
1）确定实现的业务需求：用户工资管理系统
2) 打开上篇文章中的NHibernateStudy1解决方案。向项目NhibernateSample1添加类Salary;代码如下
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> /// 工资编号
/// </summary> public virtual int Id { get { return _id; } set { _id = value; } } /// <summary> /// 雇员 /// </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> /// 工资 /// </summary> public decimal Money { get { return _money; } set { _money = value; } } }
}3) 更改User.cs,在User里面添加SalaryList属性：
1
private System.Collections.IList _salaryList;2
/// <summary>3
/// 工资列表4
/// </summary>5
public System.Collections.IList SalaryList6
{7
get8
{9
return _salaryList;10
}11
set12
{13
_salaryList = value;14
}15
}<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>5）编写类Salary的映射文件: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>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(); } } }}using System;using System.Text;using System.Collections.Generic;using Microsoft.VisualStudio.TestTools.UnitTesting;using NhibernateSample1;namespace TestProject1{ /// <summary> /// UnitTest1 的摘要说明 /// </summary> [TestClass] public class UnitTest1 { public UnitTest1() { // // TODO: 在此处添加构造函数逻辑 // } NhibernateSample1.UserSalaryFixure usf = new UserSalaryFixure();
其他测试属性 [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); } }}总结：通过进一步学习nhiberate，发现ORM框架真是非常强大。今天先到这里。明天继续。