NHibernate.3.0.Cookbook第四章第1节的翻译

Introduction

简介

　　本章中,除了最后的两个小节示例外,所有的示例开始时都遵照下面的步骤.这些步骤包含了映射模型,配置log4net和NHibernate的通用代码,此外还包含有必要的但是重复的管道代码.
1.   完成第一章中的Eg.Core项目.
2.   在解决方案中添加一个新的控制台程序.
3.   为项目添加App.config文件.

4.   依照第二章中的Configuring NHibenate with App.config和Configuring NHibernate Logging小节,在App.config中配置log4net和NHibernate.
5.   创建一个名为ExampleDataCreator 的类,代码如下:

public class ExampleDataCreator
{
  private readonly ISessionFactory _sessionFactory;
  public ExampleDataCreator(
    ISessionFactory sessionFactory)
  {
    if (sessionFactory == null)
      throw new ArgumentNullException("sessionFactory");
    _sessionFactory = sessionFactory;
  }
  public void SetUpDatabase()
  {
    using (var session = _sessionFactory.OpenSession())
    using (var tx = session.BeginTransaction())
    {
      ClearDatabase(session);
      CreateMovies(session);
      CreateBook(session);
      tx.Commit();
    }
  }
  private static void ClearDatabase(ISession session)
  {
    session
      .CreateQuery("delete from ActorRole")
      .ExecuteUpdate();
    session
      .CreateQuery("delete from Product")
      .ExecuteUpdate();
  }
  private static void CreateMovies(ISession session)
  {
    session.Save(
      new Movie()
        {
          Name = "Raiders of the Lost Ark",
          Description = "Awesome",
          UnitPrice = 9.59M,
          Director = "Steven Spielberg",
          Actors = new List<ActorRole>()
                     {
                       new ActorRole()
                         {
                           Actor = "Harrison Ford",
                           Role = "Indiana Jones"
                         }
                     }
        });
    session.Save(
      new Movie()
        {
          Name = "The Bucket List",
          Description = "Good",
          UnitPrice = 15M,
          Director = "Rob Reiner",
          Actors = new List<ActorRole>()
                     {
                       new ActorRole()
                         {
                           Actor = "Jack Nicholson",
                           Role = "Edward Cole"
                         },
                       new ActorRole()
                         {
                           Actor = "Morgan Freeman",
                           Role = "Carter Chambers"
                         }
                     }
        });
  }
  private static void CreateBook(ISession session)
  {
    session.Save(
      new Book()
        {
          Name = "NHibernate 3.0 Cookbook",
          Description = "NHibernate examples",
          UnitPrice = 50M,
          Author = "Jason Dentler",
          ISBN = "978-1-849513-04-3"
        });
  }
}

6.   创建一个名为NameAndPrice的类,代码如下:

public class NameAndPrice
{
  public NameAndPrice()
  {
  }
  public NameAndPrice(string name, decimal price)
  {
    Name = name;
    Price = price;
  }
  public string Name { get; set; }
  public decimal Price { get; set; }
}

7.   创建一个名为Queries的类,代码如下:

public class Queries
{
  private readonly ISession _session;
  public Queries(ISession session)
  {
    if (session == null)
      throw new ArgumentNullException("session");
    _session = session;
  }
}

8.   在Program.cs中, 为Program类添加下述方法:

static void RunQueries(ISession session)
{
}
static void Show(string heading,
             IEnumerable<Movie> movies)
{
  Console.WriteLine(heading);
  foreach (var m in movies)
    ShowMovie(m);
  Console.WriteLine();
}
static void Show(string heading, Book book)
{
  Console.WriteLine(heading);
  ShowBook(book);
  Console.WriteLine();
}
static void Show(string heading,
                 IEnumerable<Product> products)
{
  Console.WriteLine(heading);
  foreach (var p in products)
  {
    if (p is Movie)
    {
      ShowMovie((Movie)p);
    }
    else if (p is Book)
    {
      ShowBook((Book)p);
    }
    else
      ShowProduct(p);
  }
  Console.WriteLine();
}
static void Show(string heading,
                 decimal moneyValue)
{
  Console.WriteLine(heading);
  Console.WriteLine("{0:c}", moneyValue);
  Console.WriteLine();
}
static void Show(string heading,
                 IEnumerable<NameAndPrice> results)
{
  Console.WriteLine(heading);
  foreach (var item in results)
    ShowNameAndPrice(item);
  Console.WriteLine();
}
static void ShowNameAndPrice(NameAndPrice item)
{
  Console.WriteLine("{0:c} {1}",
                    item.Price, item.Name);
}
static void ShowProduct(Product p)
{
  Console.WriteLine("{0:c} {1}",
                    p.UnitPrice, p.Name);
}
static void ShowBook(Book b)
{
  Console.WriteLine("{0:c} {1} (ISBN {2})",
    b.UnitPrice, b.Name, b.ISBN);
}
static void ShowMovie(Movie movie)
{
  var star = movie.Actors
    .Select(actorRole => actorRole.Actor)
    .FirstOrDefault();
  Console.WriteLine("{0:c} {1} starring {2}",
    movie.UnitPrice, movie.Name, star ?? "nobody");
}

9.   在Main方法中添加下述代码:

log4net.Config.XmlConfigurator.Configure();
var nhConfig = new Configuration().Configure();
var sessionFactory = nhConfig.BuildSessionFactory();
new ExampleDataCreator(sessionFactory)
  .SetUpDatabase();
using (var session = sessionFactory.OpenSession())
using (var tx = session.BeginTransaction())
{
  RunQueries(session);
  tx.Commit();
}
Console.WriteLine("Press any key");
Console.ReadKey();

提示

　　本章中所用的这些SQL查询,嗯,实际上,整本书所用的这些SQL查询都是特定于Microsoft SQL Server 2008的,如果与你使用的RDBMS不同,那么这些示例中的SQL查询可能会略有不同.