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  • C#从数据库mysql读取数据

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Windows.Forms;
    using MySql.Data.MySqlClient;
    namespace 电子商务
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
            private void Form1_Load(object sender, EventArgs e)
            {
            }
            private void button1_Click(object sender, EventArgs e)
            {
                string str = "Host=localhost;User ID=root;Password=;Port = 3306;DataBase=animals;Charset=utf8;";
                MySqlConnection conn = new MySqlConnection(str);
                conn.Open();//
                            ////拿到数据库并打开连接
                            //string sql = "select *from student";
                            //MySqlCommand cmd = new MySqlCommand(sql, conn);
                            //MySqlDataAdapter mda = new MySqlDataAdapter(cmd);
                            //DataSet ds = new DataSet();
                            //mda.Fill(ds);
                            //dataGridView1.DataSource = ds.Tables[0];
                            ////MySqlDataReader dr = cmd.ExecuteReader();
                            //conn.Close();
                /*1.访问数据库的五大步骤
                  2.拿到要发送的sql语句
                  3.执行 sql 语句
                  4.拿到执行后的聚过
                  5.关闭连接 切记关闭连接
                */
                ////1 拿到数据库的连接 并打开连接
                //string url = "User ID=root;Password=;Host=localhost;Port=3306;Database=xx;charset=xx;";
                //MySqlConnection con = new MySqlConnection(url);
                //con.Open();
                ////2.要拿到要发送的sql语句
                //string sql = "select id from student where name='kobe'";
                //MySqlCommand com = new MySqlCommand(sql, con);
                //// 3 执行 sql 语句
                //MySqlDataReader reader = com.ExecuteReader();
                //reader.Read();// Read() 每次调用 都会从结果集中返回一行数据
                //reader.GetInt32(0);
                /*1.访问数据库的五大步骤
                  2.拿到要发送的sql语句
                  3.执行 sql 语句
                  4.拿到执行后的聚过
                  5.关闭连接 切记关闭连接
                */
                //1 拿到数据库的连接 并打开连接
                string url = "User ID=root;Password=;Host=localhost;Port=3306;Database=students;";
                MySqlConnection con = new MySqlConnection(url);
                con.Open();
                //2.要拿到要发送的sql语句
                string sql = "select *from student where name='kobe'";
                MySqlCommand com = new MySqlCommand(sql, con);
                // 3 执行 sql 语句
                MySqlDataReader reader = com.ExecuteReader();
                reader.Read();// Read() 每次调用 都会从结果集中返回一行数据
                //reader.GetInt32(0);
                Console.WriteLine(reader.GetInt32(0));
                con.Close();
                ////对数据库进行  增  删  改  查
                ////1 拿到数据库的连接 并打开连接
                //string url = "User ID=root;Password=root;Host=localhost;Port=3306;Database=students;";
                //MySqlConnection con = new MySqlConnection(url);
                //con.Open();
                //string sql = "insert into student values(11,'hahahaha','man',6)";//添加信息
                //MySqlCommand cmd = new MySqlCommand(sql, con);
                //int result = cmd.ExecuteNonQuery();
                //Console.WriteLine("数据库打开结果:"+result);
                //con.Close();
                //FindStudent("kobe");
            }
            public static bool FindStudent(string name)
            {
                bool b = false;
                string url = "User ID=root;Password=root;Host=localhost;Port=3306;Database=students;";
                MySqlConnection con = new MySqlConnection(url);
                con.Open();
                string sql = "select *from studnet where name='{0}' ";
                sql = string.Format(sql, name);
                // Console.WriteLine(sql);
                MySqlCommand cmd = new MySqlCommand(sql, con);
                MySqlDataReader reader = cmd.ExecuteReader();
                b = reader.Read();
                return b;
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/sq45711478/p/9481087.html
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