[C#] Get connection to MySql database and common CRUD operations

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[C#] Get connection to MySql database and common CRUD operations

The test is as follows:
First add the reference: MySql.Data.dll

 private string mysqlString = "server=127.0.0.1;port=3306;user=root;password=123; database=cs;";

① Establish a mysql database link

//建立mysql数据库链接
        public MySqlConnection getMySqlConn()
        {
            //string constr = "server=localhost;User Id=root;password=123456;Database=qqmusicdistinct";
            string constr = mysqlString;
            MySqlConnection mycon = new MySqlConnection(constr);
            return mycon;
        }

②Create an execution command statement object

 //建立执行命令语句对象
         public MySqlCommand getSqlCommand(String sql, MySqlConnection mysql)
         {
             MySqlCommand mySqlCommand = new MySqlCommand(sql, mysql);
             return mySqlCommand;
         }

③ Write SQL statements and process the data accordingly

//编写sql语句，对数据做相应处理
        public void setData()
        {
            MySqlConnection mysql = getMySqlConn();
            //查询sql
            String sqlSearch = "select * from student";
            //插入sql
            //String sqlInsert = "insert into student values (12,'张三',25,'大专')";
            //修改sql
            //String sqlUpdate = "update student set name='李四' where id= 3";
            //删除sql
            //String sqlDel = "delete from student where id = 12";

            //四种语句对象
            MySqlCommand mySqlCommand = getSqlCommand(sqlSearch, mysql);
            //MySqlCommand mySqlCommand = getSqlCommand(sqlInsert, mysql);
            //MySqlCommand mySqlCommand = getSqlCommand(sqlUpdate, mysql);
            //MySqlCommand mySqlCommand = getSqlCommand(sqlDel, mysql);

            mysql.Open();
　　　　　　　
            getResultset(mySqlCommand);
            //getInsert(mySqlCommand);
            //getUpdate(mySqlCommand);
            //getDel(mySqlCommand);
            //记得关闭
            mysql.Close();
        }

④Ⅰ. Query and get the result set and traverse

//查询并获得结果集并遍历
        public void getResultset(MySqlCommand mySqlCommand)
        {
            MySqlDataReader reader = mySqlCommand.ExecuteReader();
            try
            {
                while (reader.Read())
                {
                    if (reader.HasRows)
                    {
                        //MessageBox.Show("歌曲名:" + reader.GetString(1) + "|歌手:" + reader.GetString(2));
                    }
                }
            }
            catch (Exception)
            {
                MessageBox.Show("查询失败了！");
            }
            finally
            {
                reader.Close();
            }
        }

④Ⅱ. Add data

//添加数据
        public static void getInsert(MySqlCommand mySqlCommand)
        {
            try
            {
                mySqlCommand.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                String message = ex.Message;
                Console.WriteLine("插入数据失败了！" + message);
            }

        }

④Ⅲ. Modify data

//修改数据
        public static void getUpdate(MySqlCommand mySqlCommand)
        {
            try
            {
                mySqlCommand.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                String message = ex.Message;
                Console.WriteLine("修改数据失败了！" + message);
            }
        }

④Ⅳ.Deletion of data

//删除数据
        public static void getDel(MySqlCommand mySqlCommand)
        {
            try
            {
                mySqlCommand.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                String message = ex.Message;
                Console.WriteLine("删除数据失败了！" + message);
            }
        }

Total code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;


using MySql.Data.MySqlClient;

namespace WindowsFormsApplication1
{

    public partial class Form1 : Form
    {

        private string mysqlString = "server=127.0.0.1;port=3306;user=root;password=123; database=cs;";

        public MySqlConnection conn = null;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {

        }

         //建立mysql数据库链接
         public MySqlConnection getMySqlConn()
         {

             string constr = mysqlString;
             MySqlConnection mycon = new MySqlConnection(constr);
             return mycon;
         }

         //建立执行命令语句对象
         public MySqlCommand getSqlCommand(String sql, MySqlConnection mysql)
         {
             MySqlCommand mySqlCommand = new MySqlCommand(sql, mysql);
             return mySqlCommand;
         }


        private void button1_Click_1(object sender, EventArgs e)
        {

            MySqlConnection conn = getMySqlConn();
            try
            {

                conn.Open();//打开连接
                Console.WriteLine("已经建立连接");
                MySqlDataAdapter sda = new MySqlDataAdapter("select * from stu", conn);//读取表数据
                DataTable dt = new DataTable();//dt是一个表类型。
                sda.Fill(dt);//把sda读取的数据填到dt里
                dataGridView1.DataSource = dt;//把dt的内容绑定到Gridview1里显示。
            }
            catch (MySqlException ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                conn.Close();
            }
            conn.Dispose();
        }


         //添加数据
          public static void getInsert(MySqlCommand mySqlCommand)
          {
              try
              {
                  mySqlCommand.ExecuteNonQuery();
              }
              catch (Exception ex)
              {
                 String message = ex.Message;
                 Console.WriteLine("插入数据失败了！" + message);
             }
         }
        private void button2_Click(object sender, EventArgs e)
        {
             MySqlConnection mysql = getMySqlConn();

              //插入sql
              String sqlInsert = "insert into stu values ('lijie','m',23)";
              MySqlCommand mySqlCommand = getSqlCommand(sqlInsert, mysql);
              mysql.Open();
              getInsert(mySqlCommand);
              mysql.Close();
        }

           //删除数据
          public static void getDel(MySqlCommand mySqlCommand)
          {
              try
              {
                  mySqlCommand.ExecuteNonQuery();
              }
              catch (Exception ex)
              {
                 String message = ex.Message;
                 Console.WriteLine("删除数据失败了！" + message);
             }
         }


          private void button3_Click(object sender, EventArgs e)
          {
              MySqlConnection mysql = getMySqlConn();

              //插入sql
              String sqlDel = "delete from stu where name = 'lijie'";
              MySqlCommand mySqlCommand = getSqlCommand(sqlDel, mysql);
              mysql.Open();
              getDel(mySqlCommand);
              mysql.Close();
          }

        //修改数据
          public static void getUpdate(MySqlCommand mySqlCommand)
          {
              try
              {
                  mySqlCommand.ExecuteNonQuery();
              }
              catch (Exception ex)
              {
                 String message = ex.Message;
                 Console.WriteLine("修改数据失败了！" + message);
             }
         }

          private void button4_Click(object sender, EventArgs e)
          {
              MySqlConnection mysql = getMySqlConn();

              //插入sql
              String sqlUpdate = "update stu set age=0 where name='lijie'";
              MySqlCommand mySqlCommand = getSqlCommand(sqlUpdate, mysql);
              mysql.Open();
              getUpdate(mySqlCommand);
              mysql.Close();
          }
    }
}