.NET数据访问集锦（一）最”原始“的SqlHelper
时间：2010-09-28 来源：Ferry
为什么我称之为最”原始“呢？在.NET刚诞生的时候，微软给出的示例项目PetShop第一版中用的就是SqlHelper——一个数据访问类（对象），实际上也就是一系列的方法，实现数据库的增、删、改、查等功能，包括使用T-SQL和存储过程。
PetShop相关下载：PetShop1、PetShop2、PetShop3、PetShop3.5、PetShop4、PetShop5
另外还有一个示例项目duwamish。 对比.NET PetShop和Duwamish来探讨Ado.NET的数据库编程模式。
说到.NET数据访问，离不开ADO.NET ，关于ADO.NET的介绍，请参阅微软MSDN相关内容。使用ADO.NET可以访问多种数据库，如SQL Server、Oracle、Access等。
Data Access Application Block for .NET代码及使用示例：代码中已经是使用示例，所以在此不举例子，你也可以直接下载下来看具体的示例。
SqlHelper1.0代码：
// Microsoft Data Access Application Block for .NET
// http://msdn.microsoft.com/library/en-us/dnbda/html/daab-rm.asp
//
// SQLHelper.cs
//
// This file contains the implementations of the SqlHelper and SqlHelperParameterCache
// classes.
//
// For more information see the Data Access Application Block Implementation Overview.
//
//===============================================================================
// Copyright (C) 2000-2001 Microsoft Corporation
// All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR
// FITNESS FOR A PARTICULAR PURPOSE.
//==============================================================================
using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;
namespace Microsoft.ApplicationBlocks.Data
{
/// <summary>
/// The SqlHelper class is intended to encapsulate high performance, scalable best practices for
/// common uses of SqlClient.
/// </summary>
public sealed class SqlHelper
{
#region private utility methods & constructors
//Since this class provides only static methods, make the default constructor private to prevent
//instances from being created with "new SqlHelper()".
private SqlHelper() {}
/// <summary>
/// This method is used to attach array of SqlParameters to a SqlCommand.
///
/// This method will assign a value of DbNull to any parameter with a direction of
/// InputOutput and a value of null.
///
/// This behavior will prevent default values from being used, but
/// this will be the less common case than an intended pure output parameter (derived as InputOutput)
/// where the user provided no input value.
/// </summary>
/// <param name="command">The command to which the parameters will be added</param>
/// <param name="commandParameters">an array of SqlParameters tho be added to command</param>
private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
{
foreach (SqlParameter p in commandParameters)
{
//check for derived output value with no value assigned
if ((p.Direction == ParameterDirection.InputOutput) && (p.Value == null))
{
p.Value = DBNull.Value;
}
command.Parameters.Add(p);
}
}
/// <summary>
/// This method assigns an array of values to an array of SqlParameters.
/// </summary>
/// <param name="commandParameters">array of SqlParameters to be assigned values</param>
/// <param name="parameterValues">array of objects holding the values to be assigned</param>
private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
{
if ((commandParameters == null) || (parameterValues == null))
{
//do nothing if we get no data
return;
}
// we must have the same number of values as we pave parameters to put them in
if (commandParameters.Length != parameterValues.Length)
{
throw new ArgumentException("Parameter count does not match Parameter Value count.");
}
//iterate through the SqlParameters, assigning the values from the corresponding position in the
//value array
for (int i = 0, j = commandParameters.Length; i < j; i++)
{
commandParameters[i].Value = parameterValues[i];
}
}
/// <summary>
/// This method opens (if necessary) and assigns a connection, transaction, command type and parameters
/// to the provided command.
/// </summary>
/// <param name="command">the SqlCommand to be prepared</param>
/// <param name="connection">a valid SqlConnection, on which to execute this command</param>
/// <param name="transaction">a valid SqlTransaction, or 'null'</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters)
{
//if the provided connection is not open, we will open it
if (connection.State != ConnectionState.Open)
{
connection.Open();
}
//associate the connection with the command
command.Connection = connection;
//set the command text (stored procedure name or SQL statement)
command.CommandText = commandText;
//if we were provided a transaction, assign it.
if (transaction != null)
{
command.Transaction = transaction;
}
//set the command type
command.CommandType = commandType;
//attach the command parameters if they are provided
if (commandParameters != null)
{
AttachParameters(command, commandParameters);
}
return;
}
#endregion private utility methods & constructors
#region ExecuteNonQuery
/// <summary>
/// Execute a SqlCommand (that returns no resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create & open a SqlConnection, and dispose of it after we are done.
using (SqlConnection cn = new SqlConnection(connectionString))
{
cn.Open();
//call the overload that takes a connection in place of the connection string
return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
}
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns no 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.:
/// int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</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 int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns no resultset) against the specified SqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//finally, execute the command.
int retval = cmd.ExecuteNonQuery();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns no resultset) against the specified SqlConnection
/// 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.:
/// int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns no resultset) against the specified SqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//finally, execute the command.
int retval = cmd.ExecuteNonQuery();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns no resultset) against the specified
/// SqlTransaction 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.:
/// int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteNonQuery
#region ExecuteDataSet
/// <summary>
/// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create & open a SqlConnection, and dispose of it after we are done.
using (SqlConnection cn = new SqlConnection(connectionString))
{
cn.Open();
//call the overload that takes a connection in place of the connection string
return ExecuteDataset(cn, commandType, commandText, commandParameters);
}
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (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.:
/// DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="spName">the name of the stored procedure</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(string connectionString, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//create the DataAdapter & DataSet
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
//fill the DataSet using default values for DataTable names, etc.
da.Fill(ds);
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
//return the dataset
return ds;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified SqlConnection
/// 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(conn, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="spName">the name of the stored procedure</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(SqlConnection connection, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
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 a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//create the DataAdapter & DataSet
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
//fill the DataSet using default values for DataTable names, etc.
da.Fill(ds);
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
//return the dataset
return ds;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified
/// SqlTransaction 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 SqlTransaction</param>
/// <param name="spName">the name of the stored procedure</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(SqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
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 whether the connection was provided by the caller, or created by SqlHelper, so that
/// we can set the appropriate CommandBehavior when calling ExecuteReader()
/// </summary>
private enum SqlConnectionOwnership
{
/// <summary>Connection is owned and managed by SqlHelper</summary>
Internal,
/// <summary>Connection is owned and managed by the caller</summary>
External
}
/// <summary>
/// Create and prepare a SqlCommand, 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 SqlConnection, on which to execute this command</param>
/// <param name="transaction">a valid SqlTransaction, or 'null'</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParameters 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 SqlHelper</param>
/// <returns>SqlDataReader containing the results of the command</returns>
private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);
//create a reader
SqlDataReader dr;
// call ExecuteReader with the appropriate CommandBehavior
if (connectionOwnership == SqlConnectionOwnership.External)
{
dr = cmd.ExecuteReader();
}
else
{
dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return dr;
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create & open a SqlConnection
SqlConnection cn = new SqlConnection(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,SqlConnectionOwnership.Internal);
}
catch
{
//if we fail to return the SqlDatReader, we need to close the connection ourselves
cn.Close();
throw;
}
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (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.:
/// SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
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 a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//pass through the call to the private overload using a null transaction value and an externally owned connection
return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified SqlConnection
/// 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.:
/// SqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(SqlConnection connection, string spName, params object[] parameterValues)
{
//if we receive parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);
AssignParameterValues(commandParameters, parameterValues);
return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteReader(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//pass through to private overload, indicating that the connection is owned by the caller
return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified
/// SqlTransaction 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.:
/// SqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>a SqlDataReader containing the resultset generated by the command</returns>
public static SqlDataReader ExecuteReader(SqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we receive parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);
AssignParameterValues(commandParameters, parameterValues);
return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteReader
#region ExecuteScalar
/// <summary>
/// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a 1x1 resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create & open a SqlConnection, and dispose of it after we are done.
using (SqlConnection cn = new SqlConnection(connectionString))
{
cn.Open();
//call the overload that takes a connection in place of the connection string
return ExecuteScalar(cn, commandType, commandText, commandParameters);
}
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a 1x1 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.:
/// int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//execute the command & return the results
object retval = cmd.ExecuteScalar();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection
/// 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.:
/// int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(SqlConnection connection, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//execute the command & return the results
object retval = cmd.ExecuteScalar();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a 1x1 resultset) against the specified
/// SqlTransaction 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.:
/// int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(SqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteScalar
#region ExecuteXmlReader
/// <summary>
/// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
/// <returns>an XmlReader containing the resultset generated by the command</returns>
public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteXmlReader(connection, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an XmlReader containing the resultset generated by the command</returns>
public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//create the DataAdapter & DataSet
XmlReader retval = cmd.ExecuteXmlReader();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified SqlConnection
/// 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.:
/// XmlReader r = ExecuteXmlReader(conn, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid SqlConnection</param>
/// <param name="spName">the name of the stored procedure using "FOR XML AUTO"</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an XmlReader containing the resultset generated by the command</returns>
public static XmlReader ExecuteXmlReader(SqlConnection connection, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
/// <returns>an XmlReader containing the resultset generated by the command</returns>
public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of SqlParameters
return ExecuteXmlReader(transaction, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-SQL command using "FOR XML AUTO"</param>
/// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
/// <returns>an XmlReader containing the resultset generated by the command</returns>
public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//create the DataAdapter & DataSet
XmlReader retval = cmd.ExecuteXmlReader();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified
/// SqlTransaction 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.:
/// XmlReader r = ExecuteXmlReader(trans, "GetOrders", 24, 36);
/// </remarks>
/// <param name="transaction">a valid SqlTransaction</param>
/// <param name="spName">the name of the stored procedure</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 XmlReader ExecuteXmlReader(SqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we receive 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)
SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteXmlReader
}
/// <summary>
/// SqlHelperParameterCache provides functions to leverage a static cache of procedure parameters, and the
/// ability to discover parameters for stored procedures at run-time.
/// </summary>
public sealed class SqlHelperParameterCache
{
#region private methods, variables, and constructors
//Since this class provides only static methods, make the default constructor private to prevent
//instances from being created with "new SqlHelperParameterCache()".
private SqlHelperParameterCache() {}
private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
/// <summary>
/// resolve at run time the appropriate set of SqlParameters for a stored procedure
/// </summary>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="includeReturnValueParameter">whether or not to include their return value parameter</param>
/// <returns></returns>
private static SqlParameter[] DiscoverSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
{
using (SqlConnection cn = new SqlConnection(connectionString))
using (SqlCommand cmd = new SqlCommand(spName,cn))
{
cn.Open();
cmd.CommandType = CommandType.StoredProcedure;
SqlCommandBuilder.DeriveParameters(cmd);
if (!includeReturnValueParameter)
{
cmd.Parameters.RemoveAt(0);
}
SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];;
cmd.Parameters.CopyTo(discoveredParameters, 0);
return discoveredParameters;
}
}
//deep copy of cached SqlParameter array
private static SqlParameter[] CloneParameters(SqlParameter[] originalParameters)
{
SqlParameter[] clonedParameters = new SqlParameter[originalParameters.Length];
for (int i = 0, j = originalParameters.Length; i < j; i++)
{
clonedParameters[i] = (SqlParameter)((ICloneable)originalParameters[i]).Clone();
}
return clonedParameters;
}
#endregion private methods, variables, and constructors
#region caching functions
/// <summary>
/// add parameter array to the cache
/// </summary>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <param name="commandParameters">an array of SqlParamters to be cached</param>
public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
{
string hashKey = connectionString + ":" + commandText;
paramCache[hashKey] = commandParameters;
}
/// <summary>
/// retrieve a parameter array from the cache
/// </summary>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="commandText">the stored procedure name or T-SQL command</param>
/// <returns>an array of SqlParamters</returns>
public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
{
string hashKey = connectionString + ":" + commandText;
SqlParameter[] cachedParameters = (SqlParameter[])paramCache[hashKey];
if (cachedParameters == null)
{
return null;
}
else
{
return CloneParameters(cachedParameters);
}
}
#endregion caching functions
#region Parameter Discovery Functions
/// <summary>
/// Retrieves the set of SqlParameters appropriate for the stored procedure
/// </summary>
/// <remarks>
/// This method will query the database for this information, and then store it in a cache for future requests.
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <returns>an array of SqlParameters</returns>
public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
{
return GetSpParameterSet(connectionString, spName, false);
}
/// <summary>
/// Retrieves the set of SqlParameters appropriate for the stored procedure
/// </summary>
/// <remarks>
/// This method will query the database for this information, and then store it in a cache for future requests.
/// </remarks>
/// <param name="connectionString">a valid connection string for a SqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="includeReturnValueParameter">a bool value indicating whether the return value parameter should be included in the results</param>
/// <returns>an array of SqlParameters</returns>
public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
{
string hashKey = connectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter":"");
SqlParameter[] cachedParameters;
cachedParameters = (SqlParameter[])paramCache[hashKey];
if (cachedParameters == null)
{
cachedParameters = (SqlParameter[])(paramCache[hashKey] = DiscoverSpParameterSet(connectionString, spName, includeReturnValueParameter));
}
return CloneParameters(cachedParameters);
}
#endregion Parameter Discovery Functions
}
}
.NET Framework1.1时代曾经用过另外一种方式：创建一个类库项目，将所有的SQL代码都放到XML文件中（根据设计和需要，可能会有很 多个不同的XML文件），每段独立完整的SQL代码用唯一ID标识，编写根据ID读取SQL代码（包括参数）、收参数实现数据访问功能的类，然后编译成 dll，在项目中引用，实际上这也是分层了。
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