using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.OleDb;
using System.Configuration;
using System.Data.SqlClient;
using System.Data.Sql;
namespace WorkDAL
{
    public class SqlHelper
    {
        /// 连接字符串
        public static readonly string ConnectionString = ConfigurationSettings.AppSettings["StrCon"].ToString();
        SqlConnection con = new SqlConnection(ConfigurationSettings.AppSettings["StrCon"].ToString());
        //用于缓存参数的HASH表
        //private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());
        /// <returns>执行命令所影响的行数</returns>
        public static int ExecuteNonQuery(SqlConnection connection, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }
        /// <summary>
        /// 用执行的数据库连接执行一个返回数据集的sql命令
        /// </summary>
        /// <remarks>
        /// 举例:  
        ///  OleDbDataReader r = ExecuteReader(connString, "PublishOrders", new OleDbParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">一个有效的连接字符串</param>
        /// <param name="commandText">存储过程名称或者sql命令语句</param>
        /// <param name="commandParameters">执行命令所用参数的集合</param>
        /// <returns>包含结果的读取器</returns>
        /// <summary>
        /// 返回一个DataSet数据集
        /// </summary>
        /// <param name="connectionString">一个有效的连接字符串</param>
        /// <param name="cmdText">存储过程名称或者sql命令语句</param>
        /// <param name="commandParameters">执行命令所用参数的集合</param>
        /// <returns>包含结果的数据集</returns>
        /// <summary>
        /// 用指定的数据库连接字符串执行一个命令并返回一个数据集的第一列
        /// </summary>
        /// <remarks>
        ///例如:  
        ///  Object obj = ExecuteScalar(connString, "PublishOrders", new OleDbParameter("@prodid", 24));
        /// </remarks>
        ///<param name="connectionString">一个有效的连接字符串</param>
        /// <param name="commandText">存储过程名称或者sql命令语句</param>
        /// <param name="commandParameters">执行命令所用参数的集合</param>
        /// <returns>用 Convert.To{Type}把类型转换为想要的 </returns>
        public static object ExecuteScalar(string connectionString, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, connection, cmdText, commandParameters);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
        }
        /// <summary>
        /// 用指定的数据库连接执行一个命令并返回一个数据集的第一列
        /// </summary>
        /// <remarks>
        /// 例如:  
        ///  Object obj = ExecuteScalar(connString, "PublishOrders&