Question

I have 2 tables one is in local database and other one is on remote server.
I use port forwarding in C# to get my ssh remote connection to the localhost:3306 my local database is on localhost:3307

How can I copy one table to another one if they are both on localhost but with different ports.

This is my query that I want to do:

cmd = new MySqlCommand(String.Format("INSERT INTO {0} (a,b,c,d) SELECT (a,b,c,d) FROM {1}", ConfigSettings.ReadSetting("main_table"), ConfigSettings.ReadSetting("main_table")), con);

Both tables have same columns and that is why I am using only one input from config settings.

But I have 2 connections strings as they are on different ports.

con.ConnectionString = ConfigurationManager.ConnectionStrings["con1"].ConnectionString;
con2.ConnectionString = ConfigurationManager.ConnectionStrings["con2"].ConnectionString

Is there any way to get my query to work with those 2 ports as I don’t want to be using FEDERATED connection in MySql. There must be the way as they are both on the same server.

Thank you

EDIT:

Connection strings:

<add name="Con2" connectionString="server=localhost;port=3307;user id=root;Password=*****;database=data" providerName="MySql.Data.MySqlClient"/>
<add name="Con1" connectionString="server=localhost;port=3306;user id=root;Password=******;database=data" providerName="MySql.Data.MySqlClient"/>

Answer 1

Pseudocode to move data between two separate tables on two different connection

1. Create/Open the connection to the first MySql
2. Create/Run a query to get data inside a DataTable from first MySql
3. Create/Open the connection to the second MySql
4. Create/Run a query to get data inside a DataTable from second MySql without records (using WHERE 1=0 or something like that)
5. Loop on the rows of the first DataTable
6. Call ImportRow on the second table passing the values from the
   first row

7. Save the second datatable

   DataTable dtSource = new DataTable();
   using(MySqlConnection cn1 = GetConnection("first_connection_string");
   {
       cn1.Open();
       MySqlCommand cmd = new MySqlCommand("Select x,x,x,x from t1", cn1);
       MySqlDataAdapter da = new MySqlDataAdapter();
       da.SelectCommand = cmd;
       da.Fill(dtSource);
   }
   
   DataTable dtDest = new DataTable();
   using(MySqlConnection cn2 = GetConnection("second_connection_string");
   {
       cn2.Open();
       MySqlCommand cmd = new MySqlCommand("Select x,x,x,x from t2 where 1=0", cn2);
       MySqlDataAdapter da2 = new MySqlDataAdapter();
       da2.SelectCommand = cmd;
       da2.Fill(dtDest);
   
       foreach(DataRow r in dtSource)
           dtDest.ImportRow(r);
   
       da2.Update(dtDest);
   }
   

Please note that this has not been tested. Take it as experimental.

EDIT: Seeing the comments I will add another way to update the second table

    using(MySqlConnection cn2 = GetConnection("second_connection_string");
    {
        cn2.Open();
        MySqlCommand cmd = new MySqlCommand("INSERT INTO T2 (a,b) values(@a,@b)", cn2);
        cmd.Parameters.AddWithValue("@a", string.Empty); // Suppose the "a" field is a string
        cmd.Parameters.AddWithValue("@b", string.Empty); // Suppose the "b" field is a string

        foreach(DataRow r in dtSource)
        {
            cmd.Parameters["@a"].Value = r["a"].ToString();
            cmd.Parameters["@b"].Value = r["b"].ToString();
            cmd.ExecuteNonQuery();
        }
    }

This is in the case you don’t need to insert a whole record from the dtSource in the destination table. In this case I revert to an INSERT command with parameters, loop on the source table, insert in the destination table