C# 连接MySQL

1. 添加MySQL引用

安装完MySQL之后，在安装的默认目录 C:\Program Files (x86)\MySQL\Connector NET 8.0 中查找MySQLData.dll文件。

在Visual Studio 中为项目中添加引用。

2. 引入命名空间

using MySql.Data.MySqlClient;

3. 构建连接

private static MySqlConnection m_Connect = null;
private static void Connect()
{string connectStr = "server=127.0.0.1;port=3306;database=test;user=root;password=root;";m_Connect = new MySqlConnection(connectStr);
}

server=IP地址;
port=端口号;
database=数据库名字;
user=管理员账号;
password=账号的密码;

4. 增删改查

增

private static void Insert()
{try{m_Connect.Open();//string sqlStr = "Insert into users(username, password) values('takil', '789')";//string sqlStr = "Insert into users(username, password, registerdate) values('taksil', '789789', '2015-05-09')";string sqlStr = "Insert into users(username, password, registerdate) values('wilhelm', '78889', '" + DateTime.Now + "')";MySqlCommand cmd = new MySqlCommand(sqlStr, m_Connect);int result = cmd.ExecuteNonQuery();Console.WriteLine("成功影响了{0}条数据", result);}catch (Exception ex){Console.WriteLine(ex.ToString());}finally{m_Connect?.Close();}
}

删

private static void Delete()
{try{m_Connect.Open();string sql = "delete from users where username = 'takil'";MySqlCommand cmd = new MySqlCommand(sql, m_Connect);int result = cmd.ExecuteNonQuery();Console.WriteLine("成功影响了{0}条数据", result);}catch (Exception ex){Console.WriteLine(ex.ToString());}finally{ m_Connect?.Close(); }
}

改

private static void Update()
{try{m_Connect.Open();string sql = "Update users set username = 'wqrwq', password = '123' where id = 5";MySqlCommand cmd = new MySqlCommand( sql, m_Connect);int result = cmd.ExecuteNonQuery();Console.WriteLine("成功影响了{0}条数据", result);}catch (Exception ex){Console.WriteLine(ex.ToString());}finally{ m_Connect?.Close(); }
}

查

private static void Read()
{try{m_Connect.Open();string sqlStr = "select * from users";//string sqlStr = "select id, username, registerdate from users";MySqlCommand cmd = new MySqlCommand(sqlStr, m_Connect);MySqlDataReader reader = cmd.ExecuteReader();while (reader.Read()){//Console.WriteLine(reader[0].ToString() + " " + reader[1].ToString() + " " + reader[2].ToString());//Console.WriteLine(reader.GetInt32(0) + " " + reader.GetString(1) + " " + reader.GetString(2));Console.WriteLine(reader.GetInt32("id") + " " + reader.GetString("username") + " " + reader.GetString("password"));}}catch(Exception ex){Console.WriteLine(ex.ToString());}finally{m_Connect?.Close();}
}

private static void ReadCount()
{try{m_Connect.Open();string sqlStr = "select Count(*) from users";MySqlCommand cmd = new MySqlCommand(sqlStr, m_Connect);//MySqlDataReader reader = cmd.ExecuteReader();//reader.Read();//int count = Convert.ToInt32(reader[0]);//Console.WriteLine("总数为{0}", count);object result = cmd.ExecuteScalar();int count = Convert.ToInt32(result);Console.WriteLine("总数为{0}", count);}catch (Exception ex){Console.WriteLine(ex.ToString());}finally{ m_Connect?.Close(); }
}

验证

private static bool ValifyUser(string username, string password)
{try{m_Connect.Open();//string sqlStr = "select * from users where username = '" + username + "' and password = '" + password + "'";string sqlStr = "select * from users where username = @para1 and password = @para2";MySqlCommand cmd = new MySqlCommand(sqlStr, m_Connect);cmd.Parameters.AddWithValue("para1", username);cmd.Parameters.AddWithValue("para2", password);MySqlDataReader reader = cmd.ExecuteReader();if(reader.Read()){return true;}}catch (Exception ex){Console.WriteLine(ex.ToString());}finally{m_Connect?.Close();}return false;
}

因为作者精力有限，文章中难免出现一些错漏，敬请广大专家和网友批评、指正。