using System;
using System.Data.SqlClient;
using System.Data;
using System.Configuration;
using System.Xml;

namespace CJGL
{
	/// <summary>
	/// 一個輕量級的數據庫操作類，可用于簡單的分層開發。
	/// 數據庫連接配置在WEB.config中ConnectionString配置節。
	/// 程序作者：孤獨俠客 QQ：229014536 Http://loners.yer.cn
	/// </summary>
	public class DataAccess
	{
		#region 構造函數
		///<summary>
		///構造函數
		///</summary>
		public DataAccess()
		{
		}
		#endregion

		#region 配置數據庫連接字符串
		/// <summary>
		/// 配置數據庫連接字符串
		/// </summary>
		public static string ConnectionString=ConfigurationSettings.AppSettings["ConnectionString"];
		#endregion 

		#region  執行SQL語句，返回Bool值
		/// <summary>
		/// 執行SQL語句，返回Bool值
		/// </summary>
		/// <param name="sql">要執行的SQL語句</param>
		/// <returns>返回BOOL值，True為執行成功</returns>
		public bool ExecuteSQL(string sql)
		{
			SqlConnection con=new SqlConnection(DataAccess.ConnectionString);
			SqlCommand cmd=new SqlCommand(sql,con);
			try
			{
				con.Open();
				cmd.ExecuteNonQuery();
				return true;
			}
			catch
			{
				return false;
			}
			finally
			{
				con.Close();
				con.Dispose();
				cmd.Dispose();
			}
		}
		#endregion

		#region 執行SQL語句，返回SqlDataReader
		/// <summary>
		/// 執行SQL語句，返回SqlDataReader
		/// </summary>
		/// <param name="sql">要執行的SQL語句</param>
		/// <returns>返回SqlDataReader，需手工關閉連接</returns>
		public SqlDataReader GetReader(string sql)
		{
			SqlConnection con=new SqlConnection(DataAccess.ConnectionString);
			SqlCommand cmd=new SqlCommand(sql,con);
			SqlDataReader dr=null;
			try
			{
				con.Open();
				dr=cmd.ExecuteReader(CommandBehavior.CloseConnection);
			}
			catch (Exception ex)
			{
				dr.Close();
				con.Dispose();
				cmd.Dispose();
				throw new Exception(ex.ToString());
			}
			return dr;
		}
		#endregion

		#region  分頁，返回SqlDataReader
		/// <summary>
		/// 分頁，返回SqlDataReader
		/// </summary>
		/// <param name="tblName">查詢的表名</param>
		/// <param name="fldName">排序字段名</param>
		/// <param name="PageSize">每頁中記錄的數量</param>
		/// <param name="PageIndex">當前查詢的頁碼</param>
		/// <param name="OrderType">設置排序類型, 非 0 值則降序</param>
		/// <param name="strWhere">查詢條件(注意:不要加 where)</param>
		/// <returns>返回SqlDataReader，需手工關閉連接</returns>
		public SqlDataReader GetReaderPage(string tblName,string fldName,int PageSize,int PageIndex,int OrderType,string strWhere)
		{
			string strTmp,strOrder;
			string sql="";
			if (OrderType!=0)
			{
				strTmp="< (select min";
				strOrder=" order by " + fldName +" desc";
			}
			else
			{				
				strTmp=">(select max";
				strOrder=" order by " + fldName +" asc";
			}
			if (strWhere!="")
			{
				sql = "select top " + PageSize + " * from "+ tblName + " where " + fldName + strTmp + "(";
				sql+=fldName + ") from (select top " + (PageIndex-1)*PageSize +" "+ fldName + " from " + tblName + " where (" + strWhere + ") ";
				sql+=strOrder + ") as tblTmp) and (" + strWhere + ") " + strOrder;
			}
			if (PageIndex==1)
			{
				strTmp ="";
				if (strWhere != "")
				{
					strTmp = " where (" + strWhere + ")";
				}
				sql = "select top " + PageSize + " * from " + tblName + strTmp + " " + strOrder;
			}
			SqlConnection con=new SqlConnection(DataAccess.ConnectionString);
			SqlCommand cmd=new SqlCommand(sql,con);
			SqlDataReader dr=null;
			try
			{
				con.Open();
				dr=cmd.ExecuteReader(CommandBehavior.CloseConnection);
			}
			catch (Exception ex)
			{				
				dr.Close();
				con.Dispose();
				cmd.Dispose();
				throw new Exception(ex.ToString());
			}
			return dr;
		}
		#endregion

		#region  執行SQL語句，返回DataSet
		/// <summary>
		/// 執行SQL語句，返回DataSet
		/// </summary>
		/// <param name="sql">要執行的SQL語句</param>
		/// <param name="tablename">DataSet中要填充的表名</param>
		/// <returns>返回dataSet類型的執行結果</returns>
		public DataSet GetDataSet(string sql,string tablename)
		{
			DataSet ds= new DataSet();
			SqlConnection con=new SqlConnection(DataAccess.ConnectionString);
			SqlDataAdapter da=new SqlDataAdapter(sql,con);
			try
			{
				da.Fill(ds,tablename);
			}
			catch (Exception ex)
			{
				throw new Exception(ex.ToString());
			}
			finally
			{
				con.Close();
				con.Dispose();
				da.Dispose();
			}
			return ds;
		}
		#endregion

		#region  執行SQL語句，返回DataTable
		/// <summary>
		/// 執行SQL語句，返回DataTable
		/// </summary>
		/// <param name="sql">要執行的SQL語句</param>
		/// <returns>返回DataTable類型的執行結果</returns>
		public DataTable GetDataTable(string sql)  
		{
			DataSet ds= new DataSet();
			SqlConnection con=new SqlConnection(DataAccess.ConnectionString);
			SqlDataAdapter da=new SqlDataAdapter(sql,con);
			try
			{
				da.Fill(ds,"tb");
			}
			catch (Exception ex)
			{
				throw new Exception(ex.ToString());
			}
			finally
			{
				con.Close();
				con.Dispose();
				da.Dispose();
			}
			DataTable result=ds.Tables["tb"];
			return result;
		}
		#endregion

		#region  執行SQL語句并返回受影響的行數
		/// <summary>
		/// 執行SQL語句并返回受影響的行數
		/// </summary>
		/// <param name="sql">要執行的SQL語句</param>
		/// <returns>返回Int類型的受影響的行數</returns>
		public int GetCount(string sql)
		{
			SqlConnection con=new SqlConnection(DataAccess.ConnectionString);
			SqlCommand cmd=new SqlCommand(sql,con);
			try
			{
				con.Open();
				int count=(int)cmd.ExecuteScalar();
				return count;
			}
			catch 
			{
				return 0;
			}
			finally
			{
				con.Close();
				con.Dispose();
				cmd.Dispose();
			}
		}
		#endregion
		
		#region 驗證用戶是否合法管理員
		/// <summary>
		/// 驗證用戶是否合法管理員
		/// </summary>
		/// <param name="strname">要驗證的用戶名</param>
		/// <param name="strpwd">要驗證的密碼</param>
		/// <returns>返回BOOL值，True為驗證成功</returns>
		public bool CheckAdmin(string strname,string strpwd)
		{
			string sql;
			strname=NameReplace(strname);
			sql="select count(1) from administrator where username='"+ strname +"' and password='"+ strpwd +"'";
			if(GetCount(sql)>0)
			{
				return true;
			}
			else
			{
				return false;
			}
		}
		#endregion
		
		#region 驗證用戶是否合法用戶
		/// <summary>
		/// 驗證用戶是否合法用戶
		/// </summary>
		/// <param name="strname">要驗證的用戶名</param>
		/// <param name="strpwd">要驗證的密碼</param>
		/// <returns>返回BOOL值，True為驗證成功</returns>
		public bool CheckUser (string strname,string strpwd)
	  {
		   string sql;
		   strname=NameReplace(strname);
           sql="select count(1) from student where stuid='"+strname+"'and stupassword='"+strpwd+"'";
		   if(GetCount(sql)>0)
			{
				return true;
			}
			else
			{
				return false;
			}
		}
		#endregion



		#region 注冊新的用戶
		/// <summary>
		/// 注冊新的用戶
		/// </summary>
		/// <param name="strname">要注冊的用戶名</param>
		/// <param name="strpwd">要注冊的密碼</param>
		/// <returns>返回BOOL值，True為驗證成功</returns>
		public bool  newUser (string stuid,string username,string sex,string major,string tel,string address,string btime,string password)
		{
			string sql;
			username=NameReplace(username);
			 
			sql="select count(1) from student where stuid='"+stuid+"'";
			if(GetCount(sql)>0)
			{
				return false;
			}
			
			string sql2;
			sql2="insert into student (stuid,name,sex,major,tel,address,btime,stupassword) values('"+stuid +"','"+username+"','"+sex+"','"+major+"','"+tel+"','"+address+"','"+btime+"','"+password+"')";
           ExecuteSQL(sql2);
			return true;
		}
		#endregion

		#region  過濾用戶名中的非法字符
		/// <summary>
		/// 過濾用戶名中的非法字符
		/// </summary>
		/// <param name="str">要被過濾的字符串</param>
		/// <returns>返回String類型的過濾后的字符串</returns>
		public string NameReplace(string str)
		{
			str=str.Trim();
			str=str.Replace("=","");
			str=str.Replace("'","");
			return str;
		}
		#endregion

　　 

	}
}