NHibernate开发入门

首先，我们了解一下ORM是什么？
ORM指对象关系映射（英语：Object Relational Mapping，简称ORM，或O/RM，或O/R mapping），是一种程序技术，用于实现面向对象编程语言里不同类型系统的数据之间的转换。从效果上说，它其实是创建了一个可在编程语言里使用的“虚拟对象数据库”。

其次，我们需要了解.NET领域ORM框架有哪些？
在.NET平台下，关于数据持久层框架非常多，以下是主要的5种：
1．NHibernate
2．NBear
3．Castle ActiveRecord
4．iBATIS.NET
5．DAAB 微软

使用过Java的朋友都不会对Hibernate陌生。由于之前的Java经历，所以我直接选择NHibernate作为ORM框架首选。那么NHibernate是什么？

NHibernate是一个面向.NET环境的对象/关系数据库映射工具。对象/关系数据库映射（object/relational mapping，ORM）这个术语表示一种技术，用来把对象模型表示的对象映射到基于SQL的关系模型数据结构中去。

下面，我们做一个简单的NHibernate Demo。创建项目WinForm窗体项目，命名为CRMdemo，以下是解决方案截图：

解决方案项目截图

获取NHibernate

NHibernate下载地址

https://sourceforge.net/projects/nhibernate/files/NHibernate/4.0.3.GA/NHibernate-4.0.3.GA-bin.zip/download

NHibernate项目地址

https://sourceforge.net/projects/nhibernate/

为了方便，下载后将NHibernate-4.0.3.GA-bin.zip解压缩至解决方案根目录下

添加NHibernate Dll引用

添加引用

NHibernate-4.0.3.GA-binRequired_BinsNHibernate.dll

NHibernate-4.0.3.GA-binRequired_BinsIesi.Collections.dll

NHibernate-4.0.3.GA-binTestslog4net.dll

NHibernate-4.0.3.GA-binTestsNHibernate.DomainModel.dll

NHibernate-4.0.3.GA-binTests unit.framework.dll

配置hibernate.cfg.xml

复制NHibernate-4.0.3.GA-binConfiguration_TemplatesMSSQL.cfg.xml至binDebug下，重命名为hibernate.cfg.xml，并做如下配置

<!-- This is the System.Data.dll provider for SQL Server -->
    <hibernate-configuration  xmlns="urn:nhibernate-configuration-2.2" >
    <session-factory name="CRMDemo.Hibernate">
    <property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
    <property name="connection.connection_string">
    Server=Your-PCSQLEXPRESS;initial catalog=crm;Integrated Security=SSPI
    </property>
    <property name="dialect">NHibernate.Dialect.MsSql2008Dialect</property>
        <mapping assembly="CRMDemo"/>
    </session-factory>
    </hibernate-configuration>

在MSSQL中创建一张演示表employee

创建员工表employee

CREATE TABLE [dbo].[employee](
    [id] [int] IDENTITY(1,1) NOT NULL,
    [name] [nvarchar](50) NULL,
    [age] [nchar](10) NULL,
    [gender] [nchar](10) NULL,
    [email] [nvarchar](100) NULL,
    [phonenum] [nvarchar](50) NULL,
     CONSTRAINT [PK_employee] PRIMARY KEY CLUSTERED 
    (
    [id] ASC
    )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF,  ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON)  ON [PRIMARY]
    ) ON [PRIMARY]

创建Employee.cs类

    public class Employee
    {
        public virtual int id { get; set; }
        public virtual string name { get; set; }
        public virtual int age { get; set; }
        public virtual string gender { get; set; }
        public virtual string email { get; set; }
        public virtual string phonenum { get; set; }
    }

创建映射文件Employee.hbm.xml，其中字段名称必须和类属性名称一致，区分大小写。

<?xml version="1.0" ?>
    <!--
    * By huiyaosoft.com
    * build date 2015-4-12 10:10
    -->
    <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false">
    <class 
    name="CRMDemo.Employee, CRMDemo" 
    discriminator-value="0" table="employee" >
    <id 
    name="id" type="int"
    unsaved-value="null">
          <column name="id" length="4" sql-type="4" not-null="true" unique="true"
                  index="PK_employee"/>
          <generator class="native" />
    <!-- unsaved-value used to be null and generator was increment in h2.0.3 -->
    </id>
    <property name="name" type="String">
    <column name="name" length="50" sql-type="nvarchar" not-null="false"/>
    </property>
        <property name="email" type="String">
          <column name="email" length="50" sql-type="nvarchar" not-null="false"/>
        </property>
        <property name="gender" type="String">
          <column name="gender" length="10" sql-type="nchar" not-null="false"/>
        </property>
        <property name="phonenum" type="String">
          <column name="phonenum" length="50" sql-type="nvarchar" not-null="false"/>
        </property>
        <property name="age" type="int">
          <column name="age" length="4" sql-type="int" not-null="false"/>
        </property>
    </class>
 </hibernate-mapping>

设置Employee.hbm.xml为嵌入的资源

增删改查代码

添加命名空间

using NHibernate;
using NHibernate.Cfg;

查询操作，CreateQuery或CreateSqlQuery

Configuration cfg = new Configuration();
    cfg.Configure();
    ISessionFactory factory = cfg.BuildSessionFactory();
    ISession session = factory.OpenSession();
    IQuery query = session.CreateQuery("from Employee");
    IList<Employee> eList = query.List<Employee>();
    foreach (Employee item in eList)
    {
        this.textBox1.AppendText(string.Format("id:{0},name:{1},email:{2}
", item.id, item.name, item.email));
    }
    //ISQLQuery query = session.CreateSQLQuery("select * from employee").AddEntity(typeof(Employee)); 
    //IList<Employee> eList = query.List<Employee>();
    //foreach (Employee item in eList)
    //{
    //    Console.WriteLine("id:{0},name:{1},email:{2}
", item.id, item.name, item.email);
    //}
    session.Close();
    factory.Close();

增加操作session.Save(Entity)

Configuration cfg = new Configuration();
    cfg.Configure();
    ISessionFactory factory = cfg.BuildSessionFactory();
    ISession session = factory.OpenSession();
    ITransaction trans = session.BeginTransaction();
    Employee ee = new Employee();
    ee.age = 31;
    ee.name = "李四";
    ee.email = "zhang@163.com";
    ee.phonenum = "1358111111";
    ee.gender = "男";
    session.Save(ee);
    trans.Commit();
    session.Close();
    factory.Close();
    this.textBox1.AppendText("已增加一条记录
");

修改操作session.Save(Entity)

Configuration cfg = new Configuration();
    cfg.Configure();
    ISessionFactory factory = cfg.BuildSessionFactory();
    ISession session = factory.OpenSession();
    ITransaction trans = session.BeginTransaction();
    IQuery query = session.CreateQuery("from Employee where id = :id").SetString("id","1");
    IList<Employee> eList = query.List<Employee>();
    foreach (Employee item in eList)
    {
        this.textBox1.AppendText("查询到一条记录
");
        this.textBox1.AppendText(string.Format("id:{0},name:{1},email:{2}
", item.id, item.name, item.email));
        item.email = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
       session.Save(item);
    }
    trans.Commit();
    query = session.CreateQuery("from Employee where id = :id").SetString("id", "1");
    eList = query.List<Employee>();
    foreach (Employee item in eList)
    {
        this.textBox1.AppendText("修改后记录
");
        this.textBox1.AppendText(string.Format("id:{0},name:{1},email:{2}
", item.id, item.name, item.email));
    }
   session.Close();
    factory.Close();

删除操作session.Delete(Entity)

Configuration cfg = new Configuration();
    cfg.Configure();
    ISessionFactory factory = cfg.BuildSessionFactory();
    ISession session = factory.OpenSession();
    ITransaction trans = session.BeginTransaction();
    IQuery query = session.CreateQuery("from Employee where name = :name").SetString("name", "李四");
    IList<Employee> eList = query.List<Employee>();
    foreach (Employee item in eList)
    {
        this.textBox1.AppendText("查询记录
");
        this.textBox1.AppendText(string.Format("id:{0},name:{1},email:{2}
", item.id, item.name, item.email));
        session.Delete(item);
    }
    trans.Commit();
    query = session.CreateQuery("from Employee where name = :name").SetString("name", "李四");
    eList = query.List<Employee>();
    foreach (Employee item in eList)
    {
        this.textBox1.AppendText("删除后记录
");
    }
    session.Close();
    factory.Close();

来源：http://www.huiyaosoft.com/html/nhibernate.htm

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