最近看了MS的Enterprise Library ,里面有一套很强大的Data Access Application Block。
提供了很强大的基于SQL，DataObject(DataSet,DataReader)接口的快速访问数据库的
方法，并且同Configuration Application Block相结合，非常之灵活。但是灵活的同时也
增加了学习的难度和配置的复杂度。
在平常编写系统过程中，我也积累了一套SqlHelper，暂时是基于OLEDB(Connetcion).
因为它比较灵活，SQL 2000也能使用。
我的SqlHelper是轻量级的，仿Data Access Application Block的代码库。提供非常友好
的接口(不是基于ORM级别的).
下面附上相关代码，供大家学习，参考。欢迎提出修改意见：

using System;
using System.Configuration;
using System.Data;
using System.Data.OleDb;

namespace MyLib.Data
 {

public sealed class CDBConn
  {
   // Methods
   public CDBConn()
   {
    this.m_bIsInTransaction = false;
    this.m_Timeout = 30;
    this.m_objConn = new OleDbConnection(ConfigurationSettings.AppSettings["ConnectString"]);
    this.m_objConn.Open();
   }

public CDBConn(bool bOpenNow)
   {
    this.m_bIsInTransaction = false;
    this.m_Timeout = 30;
    this.m_objConn = new OleDbConnection(ConfigurationSettings.AppSettings["ConnectString"]);
    if (bOpenNow)
    {
     this.m_objConn.Open();
    }
   }

public CDBConn(string strConnectionString)
   {
    this.m_bIsInTransaction = false;
    this.m_Timeout = 30;
    this.m_objConn = new OleDbConnection(strConnectionString);
    this.m_objConn.Open();
   }

public CDBConn(string strConnectionString, bool bOpenNow)
   {
    this.m_bIsInTransaction = false;
    this.m_Timeout = 30;
    this.m_objConn = new OleDbConnection(strConnectionString);
    if (bOpenNow)
    {
     this.m_objConn.Open();
    }
   }

public void BeginTransaction()
   {
    if (!this.m_bIsInTransaction)
    {
     this.m_objCommand = new OleDbCommand();
     this.m_objCommand.Connection = this.m_objConn;
     this.m_objTransaction = this.m_objConn.BeginTransaction();
     if (this.m_Timeout >= 30)
     {
      this.m_objCommand.CommandTimeout = this.m_Timeout;
     }
     this.m_objCommand.Transaction = this.m_objTransaction;
     this.m_bIsInTransaction = true;
    }
   }

public void Close()
   {
    if (this.m_objConn.State != ConnectionState.Closed)
    {
     this.m_objConn.Close();
    }
   }

public void Commit()
   {
    if (this.m_bIsInTransaction)
    {
     this.m_objTransaction.Commit();
     this.m_bIsInTransaction = false;
     this.m_objCommand.Dispose();
    }
   }

public void Dispose()
   {
    if (this.m_objConn.State != ConnectionState.Closed)
    {
     this.m_objConn.Close();
    }
    this.m_objConn.Dispose();
   }

public DataSet ExecuteDataSet(string strSQL)
   {
           
    DataSet set1 = new DataSet();
    OleDbCommand command1 = new OleDbCommand(strSQL, this.m_objConn);
    if (this.m_Timeout >= 30)
    {
     command1.CommandTimeout = this.m_Timeout;
    }
    OleDbDataAdapter adapter1 = new OleDbDataAdapter(command1);
    adapter1.Fill(set1);
    command1.Dispose();
    adapter1.Dispose();
    return set1;
   }

public DataSet ExecuteDataSet(string strSQL, string strTable)
   {
    DataSet set1 = new DataSet();
    OleDbCommand command1 = new OleDbCommand(strSQL, this.m_objConn);
    if (this.m_Timeout >= 30)
    {
     command1.CommandTimeout = this.m_Timeout;
    }
    OleDbDataAdapter adapter1 = new OleDbDataAdapter(command1);
    adapter1.Fill(set1, strTable);
    command1.Dispose();
    adapter1.Dispose();
    return set1;
   }

public OleDbDataReader ExecuteReader(string strSQL)
   {
    OleDbCommand command1 = new OleDbCommand(strSQL, this.m_objConn);
    if (this.m_Timeout >= 30)
    {
     command1.CommandTimeout = this.m_Timeout;
    }
    OleDbDataReader reader1 = command1.ExecuteReader();
    command1.Dispose();
    return reader1;
   }

public void ExecuteSQL(string strSQL)
   {
    if (!this.m_bIsInTransaction)
    {
     OleDbCommand command1 = new OleDbCommand(strSQL, this.m_objConn);
     if (this.m_Timeout >= 30)
     {
      command1.CommandTimeout = this.m_Timeout;
     }
     command1.ExecuteNonQuery();
     command1.Dispose();
    }
    else
    {
     this.m_objCommand.CommandText = strSQL;
     this.m_objCommand.ExecuteNonQuery();
    }
   }

public int FillDataSet(ref DataSet objDataSet, string strSQL)
   {
 
    OleDbCommand command1 = new OleDbCommand(strSQL, this.m_objConn);
    if (this.m_Timeout >= 30)
    {
     command1.CommandTimeout = this.m_Timeout;
    }
    OleDbDataAdapter adapter1 = new OleDbDataAdapter(command1);
    int num1 = adapter1.Fill(objDataSet);
    command1.Dispose();
    adapter1.Dispose();
    return num1;
   }

public int FillDataSet(ref DataSet objDataSet, string strSQL, string strTable)
   {
 
    OleDbCommand command1 = new OleDbCommand(strSQL, this.m_objConn);
    if (this.m_Timeout >= 30)
    {
     command1.CommandTimeout = this.m_Timeout;
    }
    OleDbDataAdapter adapter1 = new OleDbDataAdapter(command1);
    int num1 = adapter1.Fill(objDataSet, strTable);
    command1.Dispose();
    adapter1.Dispose();
    return num1;
   }

~CDBConn()
   {
   }

public bool Lock(string[] strArrTableName)
   {
    return true;
    //  return this.m_objSync.Lock(strArrTableName);
   }
 
   public void Open()
   {
    if (this.m_objConn.State != ConnectionState.Open)
    {
     this.m_objConn.Open();
    }
   }
 
   public void Rollback()
   {
    if (this.m_bIsInTransaction)
    {
     this.m_objTransaction.Rollback();
     this.m_bIsInTransaction = false;
     this.m_objCommand.Dispose();
    }
   }

public void Update(string strSelectSQL, DataSet objDataSet)
   {
    OleDbDataAdapter adapter1;
    OleDbCommandBuilder builder1;
    if (!this.m_bIsInTransaction)
    {
     OleDbCommand command1 = new OleDbCommand(strSelectSQL, this.m_objConn);
     if (this.m_Timeout >= 30)
     {
      command1.CommandTimeout = this.m_Timeout;
     }
     adapter1 = new OleDbDataAdapter(command1);
     builder1 = new OleDbCommandBuilder(adapter1);
     adapter1.InsertCommand = builder1.GetInsertCommand();
     adapter1.DeleteCommand = builder1.GetDeleteCommand();
     adapter1.UpdateCommand = builder1.GetUpdateCommand();
     adapter1.Update(objDataSet);
     builder1.Dispose();
     command1.Dispose();
     adapter1.Dispose();
    }
    else
    {
     adapter1 = new OleDbDataAdapter(this.m_objCommand);
     builder1 = new OleDbCommandBuilder(adapter1);
     adapter1.InsertCommand = builder1.GetInsertCommand();
     adapter1.DeleteCommand = builder1.GetDeleteCommand();
     adapter1.UpdateCommand = builder1.GetUpdateCommand();
     adapter1.Update(objDataSet);
     builder1.Dispose();
     adapter1.Dispose();
    }
   }

// Properties
   public ConnectionState State
   {
    get
    {
     return this.m_objConn.State;
    }
   }

public int Timeout
   {
    get
    {
     return this.m_Timeout;
    }
    set
    {
     if (value < 1)
     {
      this.m_Timeout = 1;
     }
     else
     {
      this.m_Timeout = value;
     }
    }
   }

// Fields
   private bool m_bIsInTransaction;
   private OleDbCommand m_objCommand;
   private OleDbConnection m_objConn;
   private OleDbTransaction m_objTransaction;
   private int m_Timeout;
  }
 }