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用C#实现的数据库抽象工厂(一)

最近学习了一下设计模式，便尝试用C#对数据库的访问操作采用抽象工厂的模式实现一下，其中与标准的模式略有不同，加入了一些自己的想法，希望大家批评指正，代码共分为6个类：

(1)AbstractDbFactory.cs

using System;
using System.Data;

namespace DbService
{
/// <summary>
/// 数据库抽象工厂接口
/// </summary>
public interface AbstractDbFactory
{
/// <summary>
/// 建立默认连接
/// </summary>
/// <returns>数据库连接</returns>
IDbConnection CreateConnection();

/// <summary>
/// 根据连接字符串建立Connection对象
/// </summary>
/// <param name="strConn">连接字符串</param>
/// <returns>Connection对象</returns>
IDbConnection CreateConnection(string strConn);

/// <summary>
/// 建立Command对象
/// </summary>
/// <returns>Command对象</returns>
IDbCommand CreateCommand();

/// <summary>
/// 建立DataAdapter对象
/// </summary>
/// <returns>DataAdapter对象</returns>
IDbDataAdapter CreateDataAdapter();

/// <summary>
/// 根据Connection建立Transaction
/// </summary>
/// <param name="myDbConnection">Connection对象</param>
/// <returns>Transaction对象</returns>
IDbTransaction CreateTransaction(IDbConnection myDbConnection);

/// <summary>
/// 根据Command建立DataReader
/// </summary>
/// <param name="myDbCommand">Command对象</param>
/// <returns>DataReader对象</returns>
IDataReader CreateDataReader(IDbCommand myDbCommand);

/// <summary>
/// 获得连接字符串
/// </summary>
/// <returns>连接字符串</returns>
string GetConnectionString();
}
}


(2)Factory.cs

using System;
using System.Configuration;

namespace DbService
{
/// <summary>
/// Factory类
/// </summary>
public sealed class Factory
{
private static volatile Factory singleFactory = null;
private static object syncObj = new object();
/// <summary>
/// Factory类构造函数
/// </summary>
private Factory()
{
}

/// <summary>
/// 获得Factory类的实例
/// </summary>
/// <returns>Factory类实例</returns>
public static Factory GetInstance()
{
if(singleFactory == null)
{
lock(syncObj)
{
if(singleFactory == null)
{
singleFactory = new Factory();
}
}
}
return singleFactory;
}

/// <summary>
/// 建立Factory类实例
/// </summary>
/// <returns>Factory类实例</returns>
public AbstractDbFactory CreateInstance()
{
AbstractDbFactory abstractDbFactory = null;
switch(ConfigurationSettings.AppSettings["DatabaseType"].ToLower())
{
case "sqlserver":
{
abstractDbFactory = new SqlFactory();
break;
}
case "oledb":
{
abstractDbFactory = new OleDbFactory();
break;
}
case "odbc":
{
abstractDbFactory = new OdbcFactory();
break;
}
}
return abstractDbFactory;
}
}
}


待续......