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 的摘要说明。
/// </summary>
public class ConnDbForAcccess
{
/// <summary>
/// 连接数据库字符串
/// </summary>
private string connectionString;

/// <summary>
/// 存储数据库连接（保护类，只有由它派生的类才能访问）
/// </summary>
protected OleDbConnection Connection;

/// <summary>
/// 构造函数：数据库的默认连接
/// </summary>
public ConnDbForAcccess()
{
string connStr;
connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString.ToString();
// connStr = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"].ToString(); //从web.config配置中读取
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>
/// 构造函数：带有参数的数据库连接
/// </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>
/// 获得连接字符串
/// </summary>
public string ConnectionString
{
get
{
return connectionString;
}
}


/// <summary>
/// 执行SQL语句没有返回结果，如：执行删除、更新、插入等操作
/// </summary>
/// <param name="strSQL"></param>
/// <returns>操作成功标志</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>
/// 执行SQL语句返回结果到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>
/// 执行SQL语句返回结果到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>
/// 执行一查询语句，同时返回查询结果数目
/// </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;
}


}
}