The following are several English question and answer titles that match the content of the article: * Why Am I Unable to Retrieve Data from a MySQL Database Through SSH.NET? * Troubleshooting MySQL Connection Issues with SSH.NET: A Case Study * How to Correctly Connect to a Rem

Connection to MySQL from .NET using SSH.NET Library

Issue:

An ASP.NET/C# web page is attempting to query a MySQL database on a remote server over an SSH connection using the Renci.SshNet and mysql-connector-net libraries. However, the code is not retrieving any data from the database.

Code Snippet:

The C# code provided attempts to establish an SSH connection, forward a port, and then connect to the MySQL database. However, it fails to retrieve any data from the database.

<code class="csharp">using(var client = new SshClient("ssh server id", "sshuser", "sshpassword")) // establishing ssh connection to server where MySql is hosted
{
    client.Connect();
    if (client.IsConnected)
    {
        var portForwarded = new ForwardedPortLocal("127.0.0.1", 3306, "127.0.0.1", 3306);
        client.AddForwardedPort(portForwarded);
        portForwarded.Start();
        using (MySqlConnection con = new MySqlConnection("SERVER=127.0.0.1;PORT=3306;UID=someuser;PASSWORD=somepass;DATABASE=Dbname"))
        {
            using (MySqlCommand com = new MySqlCommand("SELECT * FROM cities", con))
            {
                com.CommandType = CommandType.CommandText;
                DataSet ds = new DataSet();
                MySqlDataAdapter da = new MySqlDataAdapter(com);
                da.Fill(ds);
                foreach (DataRow drow in ds.Tables[0].Rows)
                {
                    Console.WriteLine("From MySql: " + drow[1].ToString());
                }
            }
        }
        client.Disconnect();
    }
    else
    {
        Console.WriteLine("Client cannot be reached...");
    }
}</code>

Solution:

To fix the issue, the following modifications can be made to the code:

1. The connection string used to connect to the MySQL database has an incorrect syntax. Change the connection string to the following:

MySqlConnectionStringBuilder connBuilder = new MySqlConnectionStringBuilder();
connBuilder.AllowBatch = true;
connBuilder.Server = "portal.RemoteServer.edu";
connBuilder.Port = 3306;
connBuilder.UserID = "RemoteServerUsername";
connBuilder.Password = "RemoteServerPassword";
connBuilder.Database = "DatabaseName";

2. The SSH connection is not established properly. Ensure that the SSH connection parameters are correct and that the client is successfully connecting to the remote server.

Modified Code:

<code class="csharp">using(var client = new SshClient("portal.RemoteServer.edu", "RemoteServerUsername", "RemoteServerPassword")) // establishing ssh connection to server where MySql is hosted
{
    client.Connect();
    if (client.IsConnected)
    {
        var portForwarded = new ForwardedPortLocal("127.0.0.1", 3306, "127.0.0.1", 3306);
        client.AddForwardedPort(portForwarded);
        portForwarded.Start();
        using (MySqlConnection con = new MySqlConnection(connBuilder.ConnectionString))
        {
            using (MySqlCommand com = new MySqlCommand("SELECT * FROM Clients", con))
            {
                com.CommandType = CommandType.CommandText;
                DataSet ds = new DataSet();
                MySqlDataAdapter da = new MySqlDataAdapter(com);
                da.Fill(ds);
                foreach (DataRow drow in ds.Tables[0].Rows)
                {
                    Console.WriteLine("From MySql: " + drow[1].ToString());
                }
            }
        }
        client.Disconnect();
    }
    else
    {
        Console.WriteLine("Client cannot be reached...");
    }
}</code>

The above is the detailed content of The following are several English question and answer titles that match the content of the article: * Why Am I Unable to Retrieve Data from a MySQL Database Through SSH.NET? * Troubleshooting MySQL Connection Issues with SSH.NET: A Case Study * How to Correctly Connect to a Rem. For more information, please follow other related articles on the PHP Chinese website!