<configuration>
<appSettings/>
<connectionStrings>
<add name="ConnectionString" connectionString="PRovider=Microsoft.Jet.OLEDB.4.0;Data Source=D:/keleyi/App_Data/db.mdb;Jet OLEDB:Database PassWord=keleyi.com"
providerName="System.Data.OleDb" />
</connectionStrings>

using System;
using System.Data;
using System.Data.OleDb;
using System.Web;
using System.Web.UI;
using System.Configuration;

namespace Com.LXJ.Database
{
/// <summary>
/// conn 的摘要說明。
/// </summary>
public class ConnDbForAcccess
{
/// <summary>
/// 連接數據庫字符串
/// </summary>
private string connectionString;

/// <summary>
/// 存儲數據庫連接（保護類，只有由它派生的類才能訪問）
/// </summary>
protected OleDbConnection Connection;

/// <summary>
/// 構造函數：數據庫的默認連接
/// </summary>
public ConnDbForAcccess()
{
string connStr;
connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString.ToString();
// connStr = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"].ToString(); //從web.config配置中讀取
connectionString = connStr;
//connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + HttpContext.Current.Request.PhysicalapplicationPath + connStr;
// connectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"].ToString();
//
Connection = new OleDbConnection(connectionString);
}

/// <summary>
/// 構造函數：帶有參數的數據庫連接
/// </summary>
/// <param name="newConnectionString"></param>
public ConnDbForAcccess(string newConnectionString)
{
//connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + HttpContext.Current.Request.PhysicalApplicationPath + newConnectionString;
connectionString = newConnectionString;
Connection = new OleDbConnection(connectionString);
}

/// <summary>
/// 獲得連接字符串
/// </summary>
public string ConnectionString
{
get
{
return connectionString;
}
}

/// <summary>
/// 執行SQL語句沒有返回結果，如：執行刪除、更新、插入等操作
/// </summary>
/// <param name="strSQL"></param>
/// <returns>操作成功標志</returns>
public bool ExeSQL(string strSQL)
{
bool resultState = false;

Connection.Open();
OleDbTransaction myTrans = Connection.BeginTransaction();
OleDbCommand command = new OleDbCommand(strSQL, Connection, myTrans);

try
{
command.ExecuteNonQuery();
myTrans.Commit();
resultState = true;
}
catch
{
myTrans.Rollback();
resultState = false;
}
finally
{
Connection.Close();
}
return resultState;
}

/// <summary>
/// 執行SQL語句返回結果到DataReader中
/// </summary>
/// <param name="strSQL"></param>
/// <returns>dataReader</returns>
private OleDbDataReader ReturnDataReader(string strSQL)
{
Connection.Open();
OleDbCommand command = new OleDbCommand(strSQL, Connection);
OleDbDataReader dataReader = command.ExecuteReader();
Connection.Close();

return dataReader;
}

/// <summary>
/// 執行SQL語句返回結果到DataSet中
/// </summary>
/// <param name="strSQL"></param>
/// <returns>DataSet</returns>
public DataSet ReturnDataSet(string strSQL)
{
Connection.Open();
DataSet dataSet = new DataSet();
OleDbDataAdapter OleDbDA = new OleDbDataAdapter(strSQL, Connection);
OleDbDA.Fill(dataSet, "objDataSet");

Connection.Close();
return dataSet;
}

/// <summary>
/// 執行一查詢語句，同時返回查詢結果數目
/// </summary>
/// <param name="strSQL"></param>
/// <returns>sqlResultCount</returns>
public int ReturnSqlResultCount(string strSQL)
{
int sqlResultCount = 0;

try
{
Connection.Open();
OleDbCommand command = new OleDbCommand(strSQL, Connection);
OleDbDataReader dataReader = command.ExecuteReader();

while (dataReader.Read())
{
sqlResultCount++;
}
dataReader.Close();
}
catch
{
sqlResultCount = 0;
}
finally
{
Connection.Close();
}
return sqlResultCount;
}

}
}