复习SqlHelper

配置信息：在App.config或Web.config的Configuration节点下添加如下代码

 <connectionStrings>
    <add name="connStr" connectionString="server=.;uid=sa;pwd=****;database=****;Charset=utf8"/>
  </connectionStrings>

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class SqlHelper
    {
        //ADO.net中的SqlHelper

 public  static readonly string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;

        public static SqlConnection CreateConnection()
        {
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            return conn;
        }

        public static int ExecuteNonQuery(SqlConnection conn, string sql, params SqlParameter[] parameters)
        {
            using (SqlCommand cmd = conn.CreateCommand())
            {
                cmd.CommandText = sql;
                cmd.Parameters.AddRange(parameters);
                return cmd.ExecuteNonQuery();
            }
        }

        public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)
        {
            using (SqlConnection conn = CreateConnection())
            {
                return ExecuteNonQuery(conn, sql, parameters);
            }
        }

        public static object ExecuteScalar(SqlConnection conn, string sql, params SqlParameter[] parameters)
        {
            using (SqlCommand cmd = conn.CreateCommand())
            {
                cmd.CommandText = sql;
                cmd.Parameters.AddRange(parameters);
                return cmd.ExecuteScalar();
            }
        }

        public static object ExecuteScalar(string sql, params SqlParameter[] parameters)
        {
            using (SqlConnection conn = CreateConnection())
            {
                return ExecuteScalar(conn, sql, parameters);
            }
        }

        public static DataTable ExecuteQuery(SqlConnection conn, string sql, params SqlParameter[] parameters)
        {
            DataTable table = new DataTable();
            using (SqlCommand cmd = conn.CreateCommand())
            {
                cmd.CommandText = sql;
                cmd.Parameters.AddRange(parameters);
                using (SqlDataReader reader = cmd.ExecuteReader())
                {
                    table.Load(reader);
                    return table;
                }
            }

        }

        public static DataTable ExecuteQuery(string sql, params SqlParameter[] parameters)
        {
            using (SqlConnection conn = CreateConnection())
            {
                return ExecuteQuery(conn, sql, parameters);
            }
        }
    }
}