SQL Server -ADO.NET 增加，删除对象

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;

namespace ConsoleApp
{
    class Program
    {
        //链接字符串--链接数据库用
        private static readonly string connString = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=StudentManger;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False";
   
     

        #region 增加对象
        static void Main(string[] args)
        {
            //准备好SQL语句
            string sql = "insert into StudentClass(ClassId,ClassName) values(8,N'C#实战班')";

            //链接ADO.NETZUO数据查询

            SqlConnection conn = new SqlConnection(connString);//链接数据库(链接数据库实例)
            SqlCommand cmd = new SqlCommand(sql, conn);//发送sql命令
          
            conn.Open();//打开链接


            int result = cmd.ExecuteNonQuery();

            conn.Close();
            Console.WriteLine("返回结果" + result);
            Console.ReadKey();

            
        }
        #endregion
    }
}

   #region 删除对象
        static void Main(string[] args)
        {
            //准备好SQL语句
            string sql = "delete from StudentClass where ClassId=8";

            //链接ADO.NETZUO数据查询

            SqlConnection conn = new SqlConnection(connString);//链接数据库(链接数据库实例)
            SqlCommand cmd = new SqlCommand(sql, conn);//发送sql命令

            conn.Open();//打开链接


            int result = cmd.ExecuteNonQuery();

            conn.Close();
            Console.WriteLine("返回结果" + result);
            Console.ReadKey();


        }
        #endregion

        #region 修改对象
        static void Main(string[] args)
        {
            //准备好SQL语句
            string sql = "update StudentClass set ClassName=N'laiyui进阶版' where ClassId=6";

            //链接ADO.NETZUO数据查询

            SqlConnection conn = new SqlConnection(connString);//链接数据库(链接数据库实例)
            SqlCommand cmd = new SqlCommand(sql, conn);//发送sql命令

            conn.Open();//打开链接


            int result = cmd.ExecuteNonQuery();

            conn.Close();
            Console.WriteLine("返回结果" + result);
            Console.ReadKey();


        }
        #endregion