Agfdhyk

I tried the code and failed because of the duplication of rows in remote database, while inserting from local database.

using System.Data.SQLite;

using System.Net.NetworkInformation;

using MySql.Data.MySqlClient;

namespace super

{

public partial class neworupload : Form

{

     SQLiteConnection con = new SQLiteConnection(@"connection string");

     MySqlConnection conn;

     String connstring;

     public neworupload()

     {

          InitializeComponent();

     }

     private void button1_Click(object sender, EventArgs e)

     {

          bool connection = NetworkInterface.GetIsNetworkAvailable();

          if (connection == true)

          {

               connstring = "SERVER=your ip;PORT=port;DATABASE=dbname;UID=userid;PASSWORD=password;SslMode = none;";

               try

               {

                    con.Open();

                    MessageBox.Show("Connection success");

                    String qu = "select * from users ";

                    SQLiteCommand cmd = new SQLiteCommand(qu, con);

                    SQLiteDataReader data = cmd.ExecuteReader();

                    while (data.Read())

                    {

                         String a = data["iduser"].ToString();

                         String b = data["name"].ToString();

                         String c = data["type"].ToString();

                         String d = data["email"].ToString();

                         String f = data["hash"].ToString();

                         Console.WriteLine(a);

                         Console.WriteLine(b);

                         Console.WriteLine(c);

                         Console.WriteLine(d);

                         Console.WriteLine(f);

                         conn = new MySqlConnection();

                         conn.ConnectionString = connstring;

                         conn.Open();

                         String qudemo = "select iduser from users";

                         Console.WriteLine("dddd" + qudemo);

                         String qu1 = "INSERT INTO users(iduser,name,type,email,hash) Values(@iduser,@name,@type,@email,@hash)";

                         MySqlCommand cmd1 = new MySqlCommand(qu1, conn);

                         cmd1.Parameters.AddWithValue("@iduser", a);

                         cmd1.Parameters.AddWithValue("@name", b);

                         cmd1.Parameters.AddWithValue("@type", c);

                         cmd1.Parameters.AddWithValue("@email", d);

                         cmd1.Parameters.AddWithValue("@hash", f);

                         cmd1.ExecuteNonQuery();

                         conn.Close();

                   }

                   con.Close();

               }

               catch (MySql.Data.MySqlClient.MySqlException ex)

               {

                   Console.WriteLine(ex);

               }

           }

           else

           {

                MessageBox.Show("Check connectivity and try again!");

           }

       }

   }

}

Here local database contain 7 rows and remote database contain 5 rows. The first 5 rows in local and remote database are the same. So while we inserting query failed with duplication of rows. Actually the extra 2 rows must be inserted to the remote database. How to avoid this problem?

Store last saved User ID in your local db and when you again go to remote db to sync your data, put this where clause in your query where RemoteDB.UserID > local.LastStoredUserID. So it will only fetch new records...