如何连接mysql数据库?

uajslkp6  于 2021-06-20  发布在  Mysql
关注(0)|答案(6)|浏览(481)

我对c#编程非常陌生,但希望能够访问mysql数据库(没有钱购买ms sql)
但是我有一个问题;我知道开发c应用程序需要“mysql connector/net”和“mysql for visual studio”,但是安装应用程序的人也需要它们吗(有没有可能我可以用这个程序释放连接器dll?)
谢谢
编辑:这两个都是最终用户所必需的,还是仅仅是连接器所必需的?他们还需要什么吗?

pxq42qpu

pxq42qpu1#

您可以使用包管理器将其添加为包,这是最简单的方法。使用mysql数据库不需要其他任何东西。
也可以在包管理器控制台中运行下面的命令

PM> Install-Package MySql.Data

获取mysql.data

bmvo0sr5

bmvo0sr52#

另一个需要考虑的库是mysqlconnector,https://mysqlconnector.net/. mysql.data使用gpl许可证,而mysqlconnector是mit。

r7xajy2e

r7xajy2e3#

您必须从这里下载mysqlconnection-net。
那你需要加上 MySql.Data.DLL 对于msvisualstudio,请执行以下操作:
打开菜单项目
添加
参考
浏览到 C:\Program Files (x86)\MySQL\MySQL Connector Net 8.0.12\Assemblies\v4.5.2 添加mysql.data.dll
如果您想了解更多信息,请访问:在此处输入链接说明
要在代码中使用,必须导入库:

using MySql.Data.MySqlClient;

通过单击事件连接到mysql数据库(无ssl模式)的示例:

using System;
using System.Windows;
using MySql.Data.MySqlClient;

namespace Deportes_WPF
{

public partial class Login : Window
{
    private MySqlConnection connection;
    private string server;
    private string database;
    private string user;
    private string password;
    private string port;
    private string connectionString;
    private string sslM;

    public Login()
    {
        InitializeComponent();

        server = "server_name";
        database = "database_name";
        user = "user_id";
        password = "password";
        port = "3306";
        sslM = "none";

        connectionString = String.Format("server={0};port={1};user id={2}; password={3}; database={4}; SslMode={5}", server, port, user, password, database, sslM);

        connection = new MySqlConnection(connectionString);
    }

    private void conexion()
    {
        try
        {
            connection.Open();

            MessageBox.Show("successful connection");

            connection.Close();
        }
        catch (MySqlException ex)
        {
            MessageBox.Show(ex.Message + connectionString);
        }
    }

    private void btn1_Click(object sender, RoutedEventArgs e)
    {
        conexion();
    }
  }

}
rqqzpn5f

rqqzpn5f4#

private void Initialize()
    {
        server = "localhost";
        database = "connectcsharptomysql";
        uid = "username";
        password = "password";
        string connectionString;
        connectionString = "SERVER=" + server + ";" + "DATABASE=" + 
        database + ";" + "U`enter code here`ID=" + uid + ";" + "PASSWORD=" + password + ";";

        connection = new MySqlConnection(connectionString);
    }
fhity93d

fhity93d5#

看看下面的代码,我试了一下,发现:不是写 DBCon = DBConnection.Instance(); 你应该把 DBConnection DBCon - new DBConnection(); (对我有用)
而不是 MySqlComman cmd = new MySqlComman(query, DBCon.GetConnection()); 你应该把 MySqlCommand cmd = new MySqlCommand(query, DBCon.GetConnection()); (缺少d)

wfauudbj

wfauudbj6#

安装oracle的 MySql.Data nuget包。

using MySql.Data;
using MySql.Data.MySqlClient;

namespace Data
{
    public class DBConnection
    {
        private DBConnection()
        {
        }

        public string Server { get; set; }
        public string DatabaseName { get; set; }
        public string UserName { get; set; }
        public string Password { get; set; }

        private MySqlConnection Connection { get; set;}

        private static DBConnection _instance = null;
        public static DBConnection Instance()
        {
            if (_instance == null)
                _instance = new DBConnection();
           return _instance;
        }

        public bool IsConnect()
        {
            if (Connection == null)
            {
                if (String.IsNullOrEmpty(databaseName))
                    return false;
                string connstring = string.Format("Server={0}; database={1}; UID={2}; password={3}", Server, DatabaseName, UserName, Password);
                Connection = new MySqlConnection(connstring);
                Connection.Open();
            }

            return true;
        }

        public void Close()
        {
            Connection.Close();
        }        
    }
}

例子:

var dbCon = DBConnection.Instance();
dbCon.Server = "YourServer";
dbCon.DatabaseName = "YourDatabase";
dbCon.UserName = "YourUsername";
dbCon.Password = "YourPassword";
if (dbCon.IsConnect())
{
    //suppose col0 and col1 are defined as VARCHAR in the DB
    string query = "SELECT col0,col1 FROM YourTable";
    var cmd = new MySqlCommand(query, dbCon.Connection);
    var reader = cmd.ExecuteReader();
    while(reader.Read())
    {
        string someStringFromColumnZero = reader.GetString(0);
        string someStringFromColumnOne = reader.GetString(1);
        Console.WriteLine(someStringFromColumnZero + "," + someStringFromColumnOne);
    }
    dbCon.Close();
}

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