oledbhelper.cs

.net数据库操作类源码.分别有ms sql server , oracle , ole db , Npg的数据

		/// <returns>a dataset containing the resultset generated by the command</returns>
		public static DataSet ExecuteDataset(OleDbConnection connection, string spName, params object[] parameterValues)
		{
			//if we got parameter values, we need to figure out where they go
			if ((parameterValues != null) && (parameterValues.Length > 0)) 
			{
				//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
				OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);

				//assign the provided values to these parameters based on parameter order
				AssignParameterValues(commandParameters, parameterValues);

				//call the overload that takes an array of OleDbParameters
				return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
			}
				//otherwise we can just call the SP without params
			else 
			{
				return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
			}
		}

		/// <summary>
		/// Execute an OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbTransaction. 
		/// </summary>
		/// <remarks>
		/// e.g.:  
		///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
		/// </remarks>
		/// <param name="transaction">a valid OleDbTransaction</param>
		/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
		/// <param name="commandText">the stored procedure name or PL/SQL command</param> 
		/// <returns>a dataset containing the resultset generated by the command</returns>
		public static DataSet ExecuteDataset(OleDbTransaction transaction, CommandType commandType, string commandText)
		{
			//pass through the call providing null for the set of OleDbParameters
			return ExecuteDataset(transaction, commandType, commandText, (OleDbParameter[])null);
		}
		
		/// <summary>
		/// Execute an OleDbCommand (that returns a resultset) against the specified OleDbTransaction
		/// using the provided parameters.
		/// </summary>
		/// <remarks>
		/// e.g.:  
		///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
		/// </remarks>
		/// <param name="transaction">a valid OleDbTransaction</param>
		/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
		/// <param name="commandText">the stored procedure name or PL/SQL command</param> 
		/// <param name="commandParameters">an array of OleDbParamters used to execute the command</param>
		/// <returns>a dataset containing the resultset generated by the command</returns>
		public static DataSet ExecuteDataset(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
		{
			//create a command and prepare it for execution
			OleDbCommand cmd = new OleDbCommand();
			PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
			
			//create the DataAdapter & DataSet
			OleDbDataAdapter da = new OleDbDataAdapter(cmd);
			DataSet ds = new DataSet();

			//fill the DataSet using default values for DataTable names, etc.
			da.Fill(ds);
			
			//return the dataset
			return ds;
		}
		
		/// <summary>
		/// Execute a stored procedure via an OleDbCommand (that returns a resultset) against the specified 
		/// OleDbTransaction using the provided parameter values.  This method will query the database to discover the parameters for the 
		/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
		/// </summary>
		/// <remarks>
		/// This method provides no access to output parameters or the stored procedure's return value parameter.
		/// 
		/// e.g.:  
		///  DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
		/// </remarks>
		/// <param name="transaction">a valid OleDbTransaction</param>
		/// <param name="spName">the name of the stored prcedure</param>
		/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
		/// <returns>a dataset containing the resultset generated by the command</returns>
		public static DataSet ExecuteDataset(OleDbTransaction transaction, string spName, params object[] parameterValues)
		{
			//if we got parameter values, we need to figure out where they go
			if ((parameterValues != null) && (parameterValues.Length > 0)) 
			{
				//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
				OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);

				//assign the provided values to these parameters based on parameter order
				AssignParameterValues(commandParameters, parameterValues);

				//call the overload that takes an array of OleDbParameters
				return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
			}
				//otherwise we can just call the SP without params
			else 
			{
				return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
			}
		}

		#endregion ExecuteDataSet
		
		#region ExecuteReader

		/// <summary>
		/// this enum is used to indicate weather the connection was provided by the caller, or created by OleDbHelper, so that
		/// we can set the appropriate CommandBehavior when calling ExecuteReader()
		/// </summary>
		private enum OleDbConnectionOwnership	
		{
			/// <summary>Connection is owned and managed by OleDbHelper</summary>
			Internal, 
			/// <summary>Connection is owned and managed by the caller</summary>
			External
		}

		/// <summary>
		/// Create and prepare an OleDbCommand, and call ExecuteReader with the appropriate CommandBehavior.
		/// </summary>
		/// <remarks>
		/// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
		/// 
		/// If the caller provided the connection, we want to leave it to them to manage.
		/// </remarks>
		/// <param name="connection">a valid OleDbConnection, on which to execute this command</param>
		/// <param name="transaction">a valid OleDbTransaction, or 'null'</param>
		/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
		/// <param name="commandText">the stored procedure name or PL/SQL command</param> 
		/// <param name="commandParameters">an array of OleDbParameters to be associated with the command or 'null' if no parameters are required</param>
		/// <param name="connectionOwnership">indicates whether the connection parameter was provided by the caller, or created by OleDbHelper</param>
		/// <returns>OleDbDataReader containing the results of the command</returns>
		private static OleDbDataReader ExecuteReader(OleDbConnection connection, OleDbTransaction transaction, CommandType commandType, string commandText, OleDbParameter[] commandParameters, OleDbConnectionOwnership connectionOwnership)
		{	
			//create a command and prepare it for execution
			OleDbCommand cmd = new OleDbCommand();
			PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);
			
			//create a reader
			OleDbDataReader dr;

			// call ExecuteReader with the appropriate CommandBehavior
			if (connectionOwnership == OleDbConnectionOwnership.External)
			{
				dr = cmd.ExecuteReader();
			}
			else
			{
				dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
			}

			return dr;
		}

		/// <summary>
		/// Execute an OleDbCommand (that returns a resultset and takes no parameters) against the database specified in 
		/// the connection string. 
		/// </summary>
		/// <remarks>
		/// e.g.:  
		///  OleDbDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
		/// </remarks>
		/// <param name="connectionString">a valid connection string for an OleDbConnection</param>
		/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
		/// <param name="commandText">the stored procedure name or PL/SQL command</param>  
		/// <returns>an OleDbDataReader containing the resultset generated by the command</returns>
		public static OleDbDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
		{
			//pass through the call providing null for the set of OleDbParameters
			return ExecuteReader(connectionString, commandType, commandText, (OleDbParameter[])null);
		}

		/// <summary>
		/// Execute an OleDbCommand (that returns a resultset) against the database specified in the connection string 
		/// using the provided parameters.
		/// </summary>
		/// <remarks>
		/// e.g.:  
		///  OleDbDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
		/// </remarks>
		/// <param name="connectionString">a valid connection string for an OleDbConnection</param>
		/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
		/// <param name="commandText">the stored procedure name or PL/SQL command</param>  
		/// <param name="commandParameters">an array of OleDbParameters used to execute the command</param>
		/// <returns>an OleDbDataReader containing the resultset generated by the command</returns>
		public static OleDbDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
		{
			//create & open an OleDbbConnection
			OleDbConnection cn = new OleDbConnection(connectionString);
			cn.Open();

			try
			{
				//call the private overload that takes an internally owned connection in place of the connection string
				return ExecuteReader(cn, null, commandType, commandText, commandParameters, OleDbConnectionOwnership.Internal);
			}
			catch
			{
				//if we fail to return the OleDbDataReader, we neeed to close the connection ourselves
				cn.Close();
				throw;
			}
		}

		/// <summary>
		/// Execute a stored procedure via an OleDbCommand (that returns a resultset) against the database specified in 
		/// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the 
		/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
		/// </summary>
		/// <remarks>
		/// This method provides no access to output parameters or the stored procedure's return value parameter.
		/// 
		/// e.g.:  
		///  OleDbDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
		/// </remarks>
		/// <param name="connectionString">a valid connection string for an OleDbConnection</param>
		/// <param name="spName">the name of the stored prcedure</param>
		/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
		/// <returns>an OleDbDataReader containing the resultset generated by the command</returns>
		public static OleDbDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
		{
			//if we got parameter values, we need to figure out where they go
			if ((parameterValues != null) && (parameterValues.Length > 0)) 
			{
				//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
				OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);

				//assign the provided values to these parameters based on parameter order
				AssignParameterValues(commandParameters, parameterValues);

				//call the overload that takes an array of OleDbParameters
				return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
			}
			//otherwise we can just call the SP without params
			else 
			{
				return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
			}
		}

		/// <summary>
		/// Execute an OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbConnection. 
		/// </summary>
		/// <remarks>
		/// e.g.:  
		///  OleDbDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
		/// </remarks>
		/// <param name="connection">a valid OleDbConnection</param>
		/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
		/// <param name="commandText">the stored procedure name or PL/SQL command</param>
		/// <returns>an OleDbDataReader containing the resultset generated by the command</returns>
		public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText)