C#与SQL Server数据库连接

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

namespace Demp13
{
    class Program
    {
        static void Main(string[] args)
        {
            //1.创建连接字符串
            string str = "server=.;database=MySchool;uid=sa;pwd=密码";
            // string str = "Data Source=.;Initial Catalog=MySchool;User ID=sa;Password=accp";
            //2.创建connection对象
            SqlConnection conn = new SqlConnection(str);
            try
            {
                //3.打开链接
                conn.Open();
                Console.WriteLine("打开链接成功");
                //4.准备sql语句，创建command对象，并执行sql语句
                Console.WriteLine("请输入用户名");
                string name = Console.ReadLine();
                Console.WriteLine("请输入密码");
                string pwd = Console.ReadLine();

                string sql = "select COUNT(*) from admin where loginId='"+name+"' and loginPwd='"+pwd+"'";
                SqlCommand cmd = new SqlCommand(sql,conn);
                //5.执行sql语句，得到返回结果
               int r= Convert.ToInt32(cmd.ExecuteScalar());
               if (r > )
               {
                   Console.WriteLine("登陆成功");
               }
               else {
                   Console.WriteLine("登陆失败");
               }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally {
                //4.关闭链接
                conn.Close();
                Console.WriteLine("关闭链接成功");
            }
        }
    }
}