软讯网络 > 编程语言 > .NET > C#.NET > SqlHelper类源码
【标 题】：SqlHelper类源码
【关键字】：
SqlHelper
【来 源】：http://blog.csdn.net/sicoos/archive/2006/08/16/1075174.aspx
SqlHelper类源码
//===============================================================================
// 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 com.xxxx.DataAccess
{
/**//// <summary>
/// The SqlHelper class is intended to encapsulate high performance, scalable best practices for
/// common uses of SqlClient.
/// </summary>
public sealed class SqlHelper
{
private utility methods & constructors#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
ExecuteNonQuery#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&nb