C# MySQL 연결하기

먼저 MySQL Connector/net을 다운받습니다.

 

https://dev.mysql.com/downloads/connector/net/8.0.html

 

프로젝트에 MySQL 을 추가합니다.

 

 

 

 

 

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;
 
namespace WindowsFormsApp1
{
    class DAO
    {
        const string url = "Server=localhost;Database=test;Uid=root;Pwd=1234;Charset=utf8";
        static int boardCount { get; set; }
 
        internal int selectCount()
        {
            using (MySqlConnection conn = new MySqlConnection(url))
            {
                conn.Open();
                string sql = "SELECT count(*) cnt FROM freeboard";
 
                MySqlCommand cmd = new MySqlCommand(sql, conn);
                MySqlDataReader rdr = cmd.ExecuteReader();
                rdr.Read();
                boardCount = Convert.ToInt32(rdr["cnt"].ToString());
               
                rdr.Close();
                return boardCount;
            }
 
        }
    }
}
 

 

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;
 
namespace WindowsFormsApp1
{
    class MessageBot
    {
        private DAO dao { get; set; }
        public MessageBot(DAO dao)
        {
            this.dao = dao;
        }
        public void BotCall(object sender, EventArgs e)
        {
            int boardCount = dao.selectCount();
            Console.WriteLine(boardCount);    
        }
 
    }
}
 

 

 

 internal LetterVO newLetter()
        {
            using (MySqlConnection conn = new MySqlConnection(url))
            {
                conn.Open();
                string sql = "SELECT * from FROM letter where id = (select max(id) from letter)";
 
                MySqlCommand cmd = new MySqlCommand(sql, conn);
                MySqlDataReader rdr = cmd.ExecuteReader();
 
                rdr.Read();
                LetterVO letterVO = new LetterVO();
                letterVO.getter_setter_id = Convert.ToInt32(rdr["id"].ToString());
                
 
                rdr.Close();
                return letterVO;
            }
        }