using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;
namespace Book.DAL
{
/// <summary>
/// SqlServer数据访问帮助类
/// </summary>
public sealed class SqlHelper
{
#region 私有构造函数和方法
private SqlHelper() {}
/// <summary>
/// 将SqlParameter参数数组(参数值)分配给SqlCommand命令.
/// 这个方法将给任何一个参数分配DBNull.Value;
/// 该操作将阻止默认值的使用.
/// </summary>
/// <param>命令名</param>
/// <param>SqlParameters数组</param>
private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
{
if( command == null ) throw new ArgumentNullException( "command" );
if( commandParameters != null )
{
foreach (SqlParameter p in commandParameters)
{
if( p != null )
{
// 检查未分配值的输出参数，将其分配以DBNull.Value.
if ( ( p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input ) &&
(p.Value == null))
{
p.Value = DBNull.Value;
}
command.Parameters.Add(p);
}
}
}
}
/// <summary>
/// 将DataRow类型的列值分配到SqlParameter参数数组.
/// </summary>
/
// <param>要分配值的SqlParameter参数数组</param>
/// <param>将要分配给存储过程参数的DataRow</param>
private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow)
{
if ((commandParameters == null) || (dataRow == null))
{
return;
}
int i = 0;
// 设置参数值
foreach(SqlParameter commandParameter in commandParameters)
{
// 创建参数名称，如果不存在，只抛出一个异常.
if( commandParameter.ParameterName == null ||
commandParameter.ParameterName.Length <= 1 )
throw new Exception(
string.Format("请提供参数{0}一个有效的名称{1}.", i, commandParameter.ParameterName ) );
// 从dataRow的表中获取为参数数组中数组名称的列的索引.
// 如果存在和参数名称相同的列，则将列值赋给当前名称的参数.
if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1)
commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];
i++;
}
}
/// <summary>
/// 将一个对象数组分配给SqlParameter参数数组.
/// </summary>
/// <param>要分配值的SqlParameter参数数组</param>
/// <param>将要分配给存储过程参数的对象数组</param>
private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
{
if ((commandParameters == null) || (parameterValues == null))
{
return;
}
// 确保对象数组个数与参数个数匹配，如果不匹配，抛出一个异常.
if (commandParameters.Length != parameterValues.Length)
{
throw new ArgumentException("参数值个数与参数不匹配.");
}
// 给参数赋值
for (int i = 0, j = commandParameters.Length; i < j; i++)
{
// If the current array value derives from IDbDataParameter, then assign its Value property
if (parameterValues[i] is IDbDataParameter)
{
IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i];
if( paramInstance.Value == null )
{
commandParameters[i].Value = DBNull.Value;
}
else
{
commandParameters[i].Value = paramInstance.Value;
}
}
else if (parameterValues[i] == null)
{
commandParameters[i].Value = DBNull.Value;
}
else
{
commandParameters[i].Value = parameterValues[i];
}
}
}
/
// <summary>
/// 预处理用户提供的命令，数据库连接/事务/命令类型/参数
/// </summary>
/// <param>要处理的SqlCommand</param>
/// <param>数据库连接</param>
/// <param>一个有效的事务或者是null值</param>
/// <param>命令类型 (存储过程，命令文本, 其它.)</param>
/// <param>存储过程名或都T-SQL命令文本</param>
/// <param>和命令相关联的SqlParameter参数数组，如果没有参数为'null'</param>
/// <param><c>true</c> 如果连接是打开的，则为true，其它情况下为false.</param>
private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransa
ction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, out bool mustCloseConnection )
{
if( command == null ) throw new ArgumentNullException( "command" );
if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );
// If the provided connection is not open, we will open it
if (connection.State != ConnectionState.Open)
{
mustCloseConnection = true;
connection.Open();
}
else
{
mustCloseConnection = false;
}
// 给命令分配一个数据库连接.
command.Connection = connection;
// 设置命令文本(存储过程名或SQL语句)
command.CommandText = commandText;
// 分配事务
if (transaction != null)
{
if( transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
command.Transaction = transaction;
}
sqltransaction什么意思// 设置命令类型.
command.CommandType = commandType;
// 分配命令参数
if (commandParameters != null)
{
AttachParameters(command, commandParameters);
}
return;
}
#endregion 私有构造函数和方法结束
#region ExecuteNonQuery命令
/// <summary>
/// 执行指定连接字符串，类型的SqlCommand.
/// </summary>
/// <remarks>
/// 示例: 
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param>一个有效的数据库连接字符串</param>
/
// <param>命令类型 (存储过程，命令文本, 其它.)</param>
/// <param>存储过程名称或SQL语句</param>
/// <returns>返回命令影响的行数</returns>
public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
{
return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// 执行指定连接字符串，类型的SqlCommand.如果没有提供参数，不返回结果.
/// </summary>
/// <remarks>
/// 示例: 
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param>一个有效的数据库连接字符串</param>
/// <param>命令类型 (存储过程，命令文本, 其它.)</param>
/// <param>存储过程名称或SQL语句</param>
/// <param>SqlParameter参数数
组</param>
/// <returns>返回命令影响的行数</returns>
public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
}
}
/// <summary>
/// 执行指定连接字符串的存储过程，将对象数组的值赋给存储过程参数,
/// 此方法需要在参数缓存方法中探索参数并生成参数.
/// </summary>
/// <remarks>
/// 这个方法没有提供访问输出参数和返回值.
/// 示例: 
///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
/// </remarks>
/// <param>一个有效的数据库连接字符串/param>
/// <param>存储过程名称</param>
/// <param>分配到存储过程输入参数的对象数组</param>
/// <returns>返回受影响的行数</returns>
public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
{
if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
// 如果存在参数值
if ((parameterValues != null) && (parameterValues.Length > 0))
{
// 从探索存储过程参数(加载到缓存)并分配给存储过程参数数组.
SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
// 给存储过程参数赋值
AssignParameterValues(commandParameters, parameterValues);
return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
else
{
// 没有参数情况下
return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// 执行指定数据库连接对象的命令
/// </summary>
/// <remarks>
/// 示例: 
///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param>一个有效的数据库连接对象</param>
/// <param>命令类型(存储过程，命
令文本或其它.)</param>
/// <param>存储过程名称或T-SQL语句</param>
/// <returns>返回影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
{
return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
}
/// <summary>
/// 执行指定数据库连接对象的命令
/// </summary>
/// <remarks>
/// 示例: 
///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param>一个有效的数据库连接对象</param>
/// <param>命令类型(存储过程，命令文本或其它.)</param>
/// <param>T存储过程名称或T-SQL语句</param>
/// <param>SqlParamter参数数组</param>
/// <returns>返回影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{   
if( connection == null ) throw new ArgumentNullException( "connection" );
// 创建SqlCommand命令，并进行预处理
SqlCommand cmd = new SqlCommand();
bool mustCloseConnection = false;
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
// Finally, execute the command
int retval = cmd.ExecuteNonQuery();
// 清除参数，以便再次使用.
cmd.Parameters.Clear();
if( mustCloseConnection )
connection.Close();
return retval;
}
/// <summary>
/// 执行指定数据库连接对象的命令，将对象数组的值赋给存储过程参数.
/// </summary>
/
// <remarks>
/// 此方法不提供访问存储过程输出参数和返回值
/// 示例: 
///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
/// </remarks>
/// <param>一个有效的数据库连接对象</param>
/// <param>存储过程名</param>
/// <param>分配给存储过程输入参数的对象数组</param>
/// <returns>返回影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues)
{
if( connection == null ) throw new ArgumentNullException( "connection" );
if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
// 如果有参数值
if ((parameterValues != null) && (p

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。