NHibernate Quick Start Guide

最新推荐文章于 2025-09-12 18:08:49 发布

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原文链接：http://www.cnblogs.com/nerozhang/archive/2008/02/15/1069129.html

文章标签：

#java #数据库

本文介绍NHibernate的基本使用方法，包括实体类定义、映射文件配置、数据库操作等，并演示了一对多及多对多关系的处理。

1 实体类：

Code

using System;

using System.Collections.Generic;

using System.Text;

namespace NHibernate.Examples.QuickStart

{

public class User

{

private string id;

private string userName;

private string password;

private string emailAddress;

private DateTime lastLogon;

public User()

{

}

public virtual string Id

{

get

{ return id; }

set

{ id = value; }

}

public virtual string UserName

{

get

{ return userName; }

set

{ userName = value; }

}

public virtual string Password

{

get

{ return password; }

set

{ password = value; }

}

public virtual string EmailAddress

{

get

{ return emailAddress; }

set

{ emailAddress = value; }

}

public virtual DateTime LastLogon

{

get

{ return lastLogon; }

set

{ lastLogon = value; }

}

注意点：在属性之前要加上virtual关键字，否则运行时会报错。

2 map文件：

<?xml version="1.0" encoding="utf-8" ?>

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">

</id>

</class>

</hibernate-mapping>

注意点：如果对应的是.net framework2.0的版本，则

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">是2.2

其次是class name一定要写对。前面是要映射类的全称，后面是namespase,也就是Assembly的名称。

还有在生成操作中一定要选：嵌入的资源。

1）class: name属性指示了Post实体类的类名和所在的Assebmly的名称，NH将通过反射的方式找到所指示的实体类，关于.Net的反射的说明，请参考MSDN; table属性指示了该实体所对应的数据表的表名

2）property: 指示实体属性和数据列的如何映射。name为实体的属性名称，实体的该属性可以为public/private/protected，甚至是 internal；column指示了该属性对应的数据列，若实体属性名称和数据列名称相同（忽视大小写），可以省略；type指示了实体属性的.Net 数据类型，可以省略，NH可以自动转换；length只是对string类型的属性适用，指示了字符串的最大长度。

3）id: 指示主键。NH支持自动生成主键、数据库生成主键和手工赋值三种方式，我们这里手工赋值的方式，设定generator的class="assigned"。

3 hibernate.cfg.xml—配置文件

<?xml version="1.0" encoding="utf-8" ?>

<section

name="nhibernate"

type="System.Configuration.NameValueSectionHandler, System, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"

</configSections>

<add

key="hibernate.connection.provider"

value="NHibernate.Connection.DriverConnectionProvider"

<add

key="hibernate.dialect"

value="NHibernate.Dialect.MsSql2000Dialect"

<add

key="hibernate.connection.driver_class"

value="NHibernate.Driver.SqlClientDriver"

<add

key="hibernate.connection.connection_string"

value="Server=192.168.0.11;database=NHibernate;uid=sa;pwd=davey@citiz.net;"

</nhibernate>

</configuration>

注意：hibernate.connection.connection_string是数据库的连接字符串。

4 测试类：

using NHibernate;

using NHibernate.Cfg;

这两个是必须的。

[SetUp]

public void BuildNHibernate()

{

cfg = new Configuration();

cfg.AddAssembly("NHibernate.Examples.QuickStart");

factory = cfg.BuildSessionFactory();

session = factory.OpenSession();

}

在使用NHibernate进行数据库操作时需要以上这些东西。

3 Insert

Code

[Test]

public void AddUser()

{

User newUser = new User();

Configuration cfg = new Configuration();

cfg.AddAssembly("NHibernate.Examples.QuickStart");

ISessionFactory factory = cfg.BuildSessionFactory();

ISession session = factory.OpenSession();

ITransaction transaction = null;

try

{

transaction = session.BeginTransaction();

newUser.Id = "joe_cool";

newUser.UserName = "Joseph Cool";

newUser.Password = "abc123";

newUser.EmailAddress = "joe@cool.com";

newUser.LastLogon = DateTime.Now;

// Tell NHibernate that this object should be saved

session.Save(newUser);

// commit all of the changes to the DB and close the ISession

transaction.Commit();

session.Close();

}

catch (HibernateException ex)

{

if (transaction != null) transaction.Rollback();

throw ex;

}

finally

{

//关闭ISession

session.Close();

}

4 update:

Code

[Test]

public void UpdateUser()

{

User joeCool = (User)session.Load(typeof(User), "joe_cool");

Assert.AreEqual("Joseph Cool", joeCool.UserName);

try

{

transaction = session.BeginTransaction();

// set Joe Cool's Last Login property

joeCool.LastLogon = DateTime.Now;

// flush the changes from the Session to the Database

session.Flush();

// commit all of the changes to the DB and close the ISession

transaction.Commit();

}

catch (HibernateException ex)

{

if (transaction != null) transaction.Rollback();

throw ex;

}

finally

{

//关闭ISession

session.Close();

}

5 select

根据主键查询

IList<User> userList = session.CreateCriteria(typeof(User)).List<User>();

有条件的查询

IList<User> recentUsers = session.CreateCriteria(typeof(User))

.Add(Expression.Expression.Eq("UserName", "Joseph Cool"))

.List<User>();

利用Hql语言查询

string hql = " from User u where u.UserName = :Name ";

IQuery query = session.CreateQuery(hql);

query.SetString("Name","Joseph Cool");

IList<User> recentUsers = query.List<User>();

6 一对多，多对多关系的查询

实体类：

Category

Code

public class Category

{

private Guid _categoryId;

private string _name = string.Empty;

private IList<Item> _items;

public virtual Guid CategoryID

{

get

{ return this._categoryId; }

set

{ this._categoryId = value; }

}

public virtual string Name

{

get

{ return this._name; }

set

{ this._name = value; }

}

public virtual IList<Item> Items

{

get

{ return this._items; }

set

{ this._items = value; }

}

public Category()

{

this._items = new List<Item>();

}

Item

Code

public class Item

{

private Guid _itemId;

private string _name = string.Empty;

private Category _category;

public virtual Guid ItemID

{

get

{ return this._itemId; }

set

{ this._itemId = value; }

}

public virtual string Name

{

get

{ return this._name; }

set

{ this._name = value; }

}

public virtual Category Category

{

get

{ return this._category; }

set

{ this._category = value; }

}

类Category中包含类Item，是一对多的关系。

映射文件：

<?xml version="1.0" encoding="utf-8" ?>

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">

<id name="CategoryID" column="CategoryID" type="Guid"

unsaved-value="00000000-0000-0000-0000-000000000000">

</id>

<one-to-many class="NHibernate.Examples.OneToMany.Item, NHibernate.Examples.OneToMany" />

</bag>

</class>

<id name="ItemID" column="ItemID" type="Guid"

unsaved-value="00000000-0000-0000-0000-000000000000">

</id>

<many-to-one name="Category" class="NHibernate.Examples.OneToMany.Category, NHibernate.Examples.OneToMany"

column="CategoryID" />

</class>

</hibernate-mapping>

其中在Category中指定了一对多的关系：

且指定了级联关系。
在类Item中指定了多对一的关系：

<many-to-one name="Category" class="NHibernate.Examples.OneToMany.Category, NHibernate.Examples.OneToMany" column="CategoryID" />

测试方法1（插入）：

Code

[Test]

public void TestCascadingSave()

{

// prepare test objects

Category expectedCategory = new Category();

expectedCategory.Name = "category" + System.Environment.TickCount.ToString();

for (int i = 0; i < 10; i++)

{

Item item = new Item();

item.Name = "item" + System.Environment.TickCount.ToString();

item.Category = expectedCategory;

expectedCategory.Items.Add(item);

}

// save objects in a all-cascading way

// note: cascading option should at least set as "all" in objects.hbm.xml

transaction = session.BeginTransaction();

try

{

session.SaveOrUpdate(expectedCategory);

transaction.Commit();

}

catch

{

transaction.Rollback();

throw;

}

// that works?

Category actualCategory =

session.Get(typeof(Category), expectedCategory.CategoryID) as Category;

Assert.IsNotNull(actualCategory);

Assert.AreEqual(expectedCategory.Items.Count, actualCategory.Items.Count);

}

测试方法2（级联删除）：

Code

[Test]

public void TestCascadingDelete()

{

Category expectedCategory =

session.CreateCriteria(typeof(Category)).List()[0] as Category;

// remove category from the repository

transaction = session.BeginTransaction();

try

{

session.Delete(expectedCategory);

transaction.Commit();

}

catch

{

transaction.Rollback();

throw;

}

// that works?

Assert.AreEqual(0, session.CreateCriteria(typeof(Category)).List().Count);

Assert.AreEqual(0, session.CreateCriteria(typeof(Item)).List().Count);

}

转载于:https://www.cnblogs.com/nerozhang/archive/2008/02/15/1069129.html