using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data;/// <summary>/// sql server数据操作的底层类/// </summary>public class SQLHelper{public static string connStr = System.Configuration.ConfigurationManager.AppSettings["connStr"];//1.查询列表 GetTable/// <summary>/// 查询命令(sql 语句或过程名),返回一个数据表/// </summary>/// <param name="cmdText">命令</param>/// <param name="type">命令类型</param>/// <param name="pms">sql参数</param>/// <returns></returns>public static DataTable GetTable(string cmdText,CommandType type, params SqlParameter[] pms){SqlConnection conn = new SqlConnection(connStr);conn.Open();SqlCommand cmd = new SqlCommand(cmdText, conn);cmd.CommandType = type;if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {foreach (SqlParameter item in pms){if (item != null) //判断数组中的每一个元素是不是为null
                    {cmd.Parameters.Add(item);}}}SqlDataAdapter sda = new SqlDataAdapter(cmd);DataSet ds = new DataSet();sda.Fill(ds, "aa");conn.Close();//返回结果DataTable dt = ds.Tables["aa"];return dt;//************************************
        }//给查询列表操作写一个执行sql语句的重载/// <summary>/// 执行sql语句，返回数据表/// </summary>/// <param name="sql">sql语句</param>/// <param name="pms">sql语句所需要的参数</param>/// <returns></returns>public static DataTable GetTable(string sql, params SqlParameter[] pms){return GetTable(sql, CommandType.Text, pms);}//2.执行命令返回影响行数 ExecuteNonQuerypublic static int ExecuteNonQuery(string cmdText, CommandType type, params SqlParameter[] pms){SqlConnection conn = new SqlConnection(connStr);conn.Open();SqlCommand cmd = new SqlCommand(cmdText, conn);cmd.CommandType = type;if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {foreach (SqlParameter item in pms){if (item != null) //判断数组中的每一个元素是不是为null
                    {cmd.Parameters.Add(item);}}} int i = cmd.ExecuteNonQuery();conn.Close(); return i;}public static int ExecuteNonQuery(string sql, params SqlParameter[] pms){return ExecuteNonQuery(sql, CommandType.Text, pms);}//3.查询返回结果中的首行首列  ExecuteSinglepublic static object ExecuteSingle(string cmdText, CommandType type, params SqlParameter[] pms){SqlConnection conn = new SqlConnection(connStr);conn.Open();SqlCommand cmd = new SqlCommand(cmdText, conn);cmd.CommandType = type;if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {foreach (SqlParameter item in pms){if (item != null) //判断数组中的每一个元素是不是为null
                    {cmd.Parameters.Add(item);}}}object obj= cmd.ExecuteScalar();conn.Close();return obj;}public static object ExecuteSingle(string sql, params SqlParameter[] pms){return ExecuteSingle(sql, CommandType.Text, pms);}//4.查询返回一个DataReader对象,让别人以游标的方式去读取数据  GetDataReaderpublic static SqlDataReader GetDataReader(string cmdText, CommandType type, params SqlParameter[] pms){SqlConnection conn = new SqlConnection(connStr);conn.Open();SqlCommand cmd = new SqlCommand(cmdText, conn);cmd.CommandType = type;if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {foreach (SqlParameter item in pms){if (item != null) //判断数组中的每一个元素是不是为null
                    {cmd.Parameters.Add(item);}}}SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);return dr;}public static SqlDataReader GetDataReader(string sql, params SqlParameter[] pms){return GetDataReader(sql, CommandType.Text, pms);}}