Chapter 1. Ado.Net 数据库增删改查

Posted 2020-07-28 庚xiao午

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;   //引用命名空间

namespace 增删改查
{
    class Program
    {
        static void Main(string[] args)
        {
　　　　　　　//增：insert into    
            //1.连接数据库
            SqlConnection con = new SqlConnection("server=.; database=ADO; user=sa; pwd=ray;");

            //2.编写SQL语句
            string sql = "insert into Student values(\'钱八\',1,\'1990-01-05\',\'90\',\'22050219900105061X\',\'18853315510\')";

            //3.创建一个执行SQL语句的对象
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                con.Open();  //4.打开连接

                int z = cmd.ExecuteNonQuery();     //5.执行语句
                Console.WriteLine("成功插入了{0}行数据\\n" + sql, z);

                con.Close();    //6.关闭连接
                Console.ReadKey();
            }
        }
    }
}

            //删:delete
            SqlConnection con = new SqlConnection("server=.; database=ADO; user=sa; pwd=ray;");
            string sql = "delete from Student where Sname=\'钱八\'";
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                con.Open();
                int s = cmd1.ExecuteNonQuery();
                Console.WriteLine("成功删除了{0}行数据\\n" + sql, s);
                con.Close();
                Console.ReadKey();
            }

            //(3)改:update...set
            SqlConnection con = new SqlConnection("server=.; database=ADO; user=sa; pwd=ray;");
            string sql = "update Student set Sname=\'张小三\',Sbirthday=\'2000-01-01\',Sscore=100 where Scode=10001";
            using (SqlCommand cmd=new SqlCommand(sql,con))
            {
                con.Open();
                int g = cmd.ExecuteNonQuery();
                Console.WriteLine("成功更改了{0}行数据\\n"+sql,g);
                con.Close();
                Console.ReadKey();
            }

            //（4）查：select
            SqlConnection con = new SqlConnection("server=.; database=ADO; user=sa; pwd=ray;");
            string sql = "select count(*) from Student";
            using (SqlCommand cmd=new SqlCommand(sql,con))
            {
                con.Open();
                object c=cmd.ExecuteScalar();
                Console.WriteLine("Student表中共有{0}条数据",c);
                con.Close();
                Console.ReadKey();
            }