adohelper.cs

C#编写的OleDb数据库连接通用类库

using System;
using System.Data;
using System.Configuration;
using System.Data.SqlClient;
using System.Data.OleDb;
using IBMDADB2Lib;
using HR1930.COM.Util;


namespace HR1930.COM.DB
{
	/// <summary>
	/// Summary description for ADOHelper.
	/// </summary>
	public class ADOHelper
	{
		
		// private member variables
		OleDbConnection con;				
		static String m_ConnectionString;

		public ADOHelper()
		{
			con = new OleDbConnection(ADOHelper.ConnectionString());
		
		}
		public DataSet ExecuteGet(string cmd)
		{
			this.CheckConnection();
			
			DataSet dataSet = new DataSet();

			try
			{
				OleDbCommand dataCommand = new OleDbCommand(cmd,con);
				OleDbDataAdapter dataAdapter = new OleDbDataAdapter();
				dataAdapter.SelectCommand = dataCommand;
						
				dataAdapter.Fill(dataSet, "recordSet");
							
			}
			catch(SqlException se)
			{
				ErrorLog el = new ErrorLog(se);
				throw new Exception("Error in SQL", se);
			}
			this.Dispose();
			return dataSet;
		}
		public OleDbDataReader ExecuteRead(String cmd)
		{
			this.CheckConnection();

			OleDbDataReader dr = null;
			
			try
			{
				OleDbCommand dc = new OleDbCommand(cmd, con);
				dr = dc.ExecuteReader();
				return dr;
			}
			catch(SqlException se)
			{
				ErrorLog el = new ErrorLog(se);
			}
			this.Dispose();
			return dr;
		}
		public void ExecuteUpdate(string cmd)
		{
			this.CheckConnection();
			try
			{
				OleDbCommand dc = new OleDbCommand(cmd, con);
				dc.ExecuteNonQuery();
			}
			catch(SqlException se)
			{
				ErrorLog el = new ErrorLog(se);
			}
			this.Dispose();
			return; 			
		}
		private void CheckConnection()
		{
			try
			{
				if (con.State != ConnectionState.Open)
					con.Open();
			}
			catch (System.Data.SqlClient.SqlException se)
			{
				ErrorLog el = new ErrorLog(se);
				throw new Exception("Failed to Open connection.", se);
			}
		}
		public static String ConnectionString()
		{
			// Pull the ConnectionString from the ASP+ AppSettings section.
			// Cache in static field for faster repeat access.
			if (m_ConnectionString == null) 
			{
				m_ConnectionString = (String) ConfigurationSettings.AppSettings["ConnectionString"];
	
				if (m_ConnectionString == null) 
				{
					throw new Exception("Connect string value not set in Web.config");
				}
			}
			return m_ConnectionString;
			
		}

		public void Dispose()
		{
			try
			{
				if (con.State == ConnectionState.Open)
					con.Close();
				//con = null;
			}
			catch(Exception e)
			{
				ErrorLog el = new ErrorLog(e);
				
			}
		}
	}
}