sqlhelper

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Data;
using System.Data.SqlClient;

namespace DB
{
    class SqlHelper
    {
        ///读取存放在web.config文件里的数据库连接字符串
        private static string ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;

        ///封装Command对象的ExecuteNonQuery方法，对数据库进行更新，删除和插入数据
        public static int ExecuteNonQuery(string sql)
        {
            using (SqlConnection conn = new SqlConnection(ConnectionString))
            {
                SqlCommand cmd = new SqlCommand(sql, conn);
                conn.Open();
                return cmd.ExecuteNonQuery();

            }
        }

        ///返回一个数据集DataSet
        public static DataSet ExecuteDataSet(string sql)
        {
            using (SqlConnection conn = new SqlConnection(ConnectionString))
            {
                SqlDataAdapter sda = new SqlDataAdapter(sql, conn);
                DataSet ds = new DataSet();
                sda.Fill(ds);
                return ds;
            }
        }

        public static DataSet ExecuteDataSet(string sql, string strTableName)
        {
            using (SqlConnection conn = new SqlConnection(ConnectionString))
            {
                SqlDataAdapter sda = new SqlDataAdapter(sql, conn);
                DataSet ds = new DataSet();
                sda.Fill(ds,strTableName);
                return ds;
            }
        }   

 

        ///填充SqlDataReader对象
        public static SqlDataReader ExcuteReaderSql(string sql)
        {
            using (SqlConnection conn = new SqlConnection(ConnectionString))
            {
                SqlCommand cmd = new SqlCommand(sql, conn);
                conn.Open();
                return cmd.ExecuteReader();  

            }
        }

        ///封装Command对象的ExecuetScalar方法，返回sql查询语句的首行首列
        public static object ExecuteScalar(string sql)
        {
            using (SqlConnection conn = new SqlConnection(ConnectionString))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                return cmd.ExecuteScalar();
            }
        }

    }
}