sql help

//===============================================================================
// This file is based on the Microsoft Data Access Application Block for .NET
// 提供ＤＡＬ类访问数据库的方法
//===============================================================================
using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Collections;
namespace XNCJWC.DBUtility
{
/// <summary>
/// The SqlHelper class is intended to encapsulate high performance, 
/// scalable best practices for common uses of SqlClient.
/// </summary>
public abstract class SqlHelper
    {
//数据连接字符串
public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["SQLConnString1"].ConnectionString;
// Hashtable to 存放参数
private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());
/// <summary>
/// 执行一个不返回结果集的sql语句
/// </summary>
/// <remarks>
/// e.g.:  
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">连接字符串</param>
/// <param name="commandType">命令类型(过程、文本) (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">命令的参数组</param>
/// <returns>返回受此命令影响的行数</returns>
public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            SqlConnection conn = new SqlConnection(connectionString);
int val = -1;
try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
            }
catch (Exception e)
            {
throw e;
            }
finally
            {
                conn.Close();
            }
return val;
        }
/// <summary>
/// 执行一个不返回结果集的sql命令
/// </summary>
/// <remarks>
/// e.g.:  
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">数据库连接</param>
/// <param name="commandType">命令类型(过程、文本)  (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">a命令的参数组</param>
/// <returns>回受此命令影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
return val;
        }
/// <summary>
/// Execute a SqlCommand (that returns no resultset) using an existing SQL Transaction 
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:  
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">an existing sql transaction</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 trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
return val;
        }
/// <summary>
/// 行一个返回结果集的命令
/// </summary>
/// <remarks>
/// e.g.:  
///  SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">数据库连接字符串</param>
/// <param name="commandType">命令类型(过程、文本)  (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">a命令的参数组</param>
/// <returns>A SqlDataReader containing the results</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            SqlConnection conn = new SqlConnection(connectionString);
// we use a try/catch here because if the method throws an exception we want to 
// close the connection throw code, because no datareader will exist, hence the 
// commandBehaviour.CloseConnection will not work
try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
return rdr;
            }
catch
            {
                conn.Close();
throw;
            }
        }
/// <summary>
/// 行一个返回结果集的命令
/// </summary>
/// <remarks>
/// e.g.:  
///  SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">数据库连接字符串</param>
/// <param name="commandType">命令类型(过程、文本)  (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">a命令的参数组</param>
/// <returns>A SqlDataReader containing the results</returns>
public static DataSet ExecuteReaderDataSet(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            SqlConnection conn = new SqlConnection(connectionString);
            DataSet ds = new DataSet();
// we use a try/catch here because if the method throws an exception we want to 
// close the connection throw code, because no datareader will exist, hence the 
// commandBehaviour.CloseConnection will not work
try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
// SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                SqlDataAdapter sda = new SqlDataAdapter(cmd);
                sda.Fill(ds);
                cmd.Parameters.Clear();
                conn.Close();
return ds;
            }
catch
            {
                conn.Close();
throw;
            }
        }
/// <summary>
/// 执行查询，并返回查询所返回的结果集中第一行的第一列。忽略其他列或行。
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:  
///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">an existing sql transaction</param>
/// <param name="commandType">命令类型(过程、文本)  (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">a命令的参数组</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
object val = null;
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
            val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
return val;
        }
/// <summary>
/// 执行查询，并返回查询所返回的结果集中第一行的第一列。忽略其他列或行。
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:  
///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">数据库连接字符串</param>
/// <param name="commandType">命令类型(过程、文本)  (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">a命令的参数组</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            SqlConnection connection = new SqlConnection(connectionString);
object val = null;
try
            {
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
                val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
            }
catch (Exception e)
            {
throw e;
            }
finally
            {
                connection.Close();
            }
return val;
        }
/// <summary>
/// 执行查询，并返回查询所返回的结果集中第一行的第一列。忽略其他列或行。
/// </summary>
/// <remarks>
/// e.g.:  
///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">数据库连接</param>
/// <param name="commandType">命令类型(过程、文本)  (stored procedure, text, etc.)</param>
/// <param name="commandText">储存过程名或sql语句</param>
/// <param name="commandParameters">a命令的参数组</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
return val;
        }
/// <summary>
/// add parameter array to the cache
/// </summary>
/// <param name="cacheKey">Key to the parameter cache</param>
/// <param name="cmdParms">an array of SqlParamters to be cached</param>
public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)
        {
            parmCache[cacheKey] = commandParameters;
        }
/// <summary>
/// Retrieve cached parameters
/// </summary>
/// <param name="cacheKey">key used to lookup parameters</param>
/// <returns>Cached SqlParamters array</returns>
public static SqlParameter[] GetCachedParameters(string cacheKey)
        {
            SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];
if (cachedParms == null)
return null;
            SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];
for (int i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();
return clonedParms;
        }
/// <summary>
/// Prepare a command for execution
/// </summary>
/// <param name="cmd">SqlCommand object</param>
/// <param name="conn">SqlConnection object</param>
/// <param name="trans">SqlTransaction object</param>
/// <param name="cmdType">Cmd type e.g. stored procedure or text</param>
/// <param name="cmdText">Command text, e.g. Select * from Products</param>
/// <param name="cmdParms">SqlParameters to use in the command</param>
private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
        {
if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = cmdType;
if (cmdParms != null)
            {
foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }
#region 返回数据集
/// <summary>
/// 返回数据集
/// </summary>
/// <param name="sqlstring">SQL语句</param>
/// <returns>数据集</returns>
public static DataSet GetDs(string connectionString, string sqlString)
        {
            SqlConnection con = new SqlConnection(connectionString);
            DataSet ds = null;
try
            {
                con.Open();
                SqlDataAdapter sda = new SqlDataAdapter(sqlString, con);
                ds = new DataSet();
                sda.Fill(ds);
            }
catch (Exception e)
            {
throw e;
            }
finally
            {
                con.Close();
                con.Dispose();
            }
return ds;
        }
#endregion
#region 获取数据视图
/// <summary>
/// 获取数据视图
/// </summary>
/// <param name="sqlstring">SQL语句</param>
/// <returns>数据视图</returns>
public static DataView GetDv(string connectionString, string sqlString)
        {
return GetDs(connectionString, sqlString).Tables[0].DefaultView;
        }
#endregion
#region 获取数据表
/// <summary>
/// 获取数据表
/// </summary>
/// <param name="sqlstring">SQL语句</param>
/// <returns>数据表</returns>
public static DataTable GetDt(string connectionString, string sqlString)
        {
            DataTable dt = GetDs(connectionString, sqlString).Tables[0];
return dt;
        }
#endregion
    }
}