Question

I have some mysql problem, I have a column named ‘transactionNumber’ and ‘counter’.

transactionNumber values can be something like this: (letters are not included)

a. 12345, 1234566
b. 9876, 98332, 23423
c. 12347
d. - 

‘counter’ column is a field that counts how many transactionNumber in a row. For example above letter ‘a’ has 2 transactionNumber, letter ‘b’ has 3 etc. letter ‘d’ counts as 1.

But counter column are empty when the application is started. So I created a method that will count the transactionNUmber for each rows and Update the counter column.

Here’s my method:

private void TransactionNumberCounter(DataSet dsData)
{
    for (int i = 0; i < dsData.Tables["data"].Rows.Count; i++)
    {
        DataRow dRow = dsData.Tables["data"].Rows[i];

        string tNumber = dRow.ItemArray.GetValue(1).ToString();
        string id = dRow.ItemArray.GetValue(0).ToString();

        string[] numbers = tNumbers.Split(',');

        char[] arr = new char[] { '\t', '\n' };
        int tNumberCounter= 0;

        List<string> listAccNumbers = new List<string>();

        foreach (string number in numbers)
            listAccNumbers.Add(number.TrimStart(arr));

        tNumberCounter = listAccNumbers.Count;

        string query = @"UPDATE bartran SET aNumberCounter = ? WHERE id = ?;";

        OdbcParameter[] parameters = new OdbcParameter[]{
        new OdbcParameter("?", aNumberCounter),
        new OdbcParameter("?", id)
        };

        DBServer.ExecuteQuery(query, "database_name", parameters);
    }
}

This method works. But if there are thousand of rows to be count I get an error:

Can't connect to MySQL server on "localhost" (10061)"

So I try here to ask for help for you guys. How can I count t.Number and update counter field base on the count on page-load. Thanks in advance!

Any other approach that may works?

EDIT: 

Here’s the DBServer Class:

using System;
using System.Data;
using System.Data.Odbc;

public static class DBServer
{
//Test
private const string Server = "localhost";
private const string Uid = "root";
private const string Pwd = "defaultpass";

//LIVE
//private const string Server = "ipaddress";
//private const string Uid = "root";
//private const string Pwd = "password";

public static DataTable GetTable(string query, string database)
{
    using (OdbcConnection cn = new OdbcConnection(
        string.Format("Driver={{MySQL ODBC 5.1 Driver}};Server={0};dataBase={1};User={2};Password={3};Option=3;",
        Server, database, Uid, Pwd)))
    {

        using (OdbcCommand cmd = new OdbcCommand(query, cn))
        {
            DataTable dt = new DataTable();

            cn.Open();

            using (OdbcDataReader rdr = cmd.ExecuteReader())
            {
                dt.Load(rdr);

                return dt;
            }
        }
    }
}

public static DataTable GetTable(string query, string database, OdbcParameter[] parameters)
{
    using (OdbcConnection cn = new OdbcConnection(
        string.Format("Driver={{MySQL ODBC 5.1 Driver}};Server={0};database={1};User={2};Password={3};Option=3;",
        Server, database, Uid, Pwd)))
    {
        using (OdbcCommand cmd = new OdbcCommand(query, cn))
        {
            if (parameters != null)
                cmd.Parameters.AddRange(parameters);

            DataTable dt = new DataTable();

            cn.Open();

            using (OdbcDataReader rdr = cmd.ExecuteReader())
            {
                dt.Load(rdr);

                return dt;
            }
        }
    }
}

/// <summary>
/// Executes query to the database (Parameterized)
/// </summary>
/// <param name="query">Query String</param>
/// <param name="database">Target Database</param>
/// <param name="parameters">Collection of parameters</param>
/// <returns>Number of affected records</returns>
public static int ExecuteQuery(string query, string database, OdbcParameter[] parameters)
{
    using (OdbcConnection cn = new OdbcConnection( string.Format("Driver={{MySQL ODBC 5.1 Driver}};Server={0};database={1};User={2};Password={3};Option=3;",
        Server, database, Uid, Pwd)))
    {
        using (OdbcCommand cmd = new OdbcCommand(query,cn))
        {
            if (parameters != null)
                cmd.Parameters.AddRange(parameters);

            cn.Open();

            return cmd.ExecuteNonQuery();
        }
    }
}

/// <summary>
/// Check if the query has record (Parameterized)
/// </summary>
/// <param name="query">Query string</param>
/// <param name="database">Target database</param>
/// <param name="parameters">Collection of parameters</param>
/// <returns>true if has record else false</returns>
public static bool HasRecord(string query, string database, OdbcParameter[] parameters)
{
    using (OdbcConnection cn = new OdbcConnection( string.Format("Driver={{MySQL ODBC 5.1 Driver}};Server={0};database={1};User={2};Password={3};Option=3;",
        Server, database, Uid, Pwd)))
    {
        using (OdbcCommand cmd = new OdbcCommand(query,cn))
        {
            if (parameters != null)
                cmd.Parameters.AddRange(parameters);               

            cn.Open();

            using (OdbcDataReader reader = cmd.ExecuteReader())
            {
                return reader.HasRows;
            }
        }
    }
}

/// <summary>
/// Check if the query has record
/// </summary>
/// <param name="query">Query string</param>
/// <param name="database">Target database</param>
/// <returns>true if has record else false</returns>
public static bool HasRecord(string query, string database)
{
    using (OdbcConnection cn = new OdbcConnection(string.Format("Driver={{MySQL ODBC 5.1 Driver}};Server={0};database={1};User={2};Password={3};Option=3;",
        Server, database, Uid, Pwd)))
    {
        using (OdbcCommand cmd = new OdbcCommand(query, cn))
        {
            cn.Open();

            using (OdbcDataReader reader = cmd.ExecuteReader())
            {
                return reader.HasRows;
            }
        }
    }
}

public static DataTable CallStoredProcedure(string query, string database, OdbcParameter[] parameters)
{
    using (OdbcConnection cn = new OdbcConnection(
        string.Format("Driver={{MySQL ODBC 5.1 Driver}};Server={0};database={1};User={2};Password={3};Option=3;",
        Server, database, Uid, Pwd)))
    {
        cn.Open();
        using (OdbcCommand cmd = new OdbcCommand(query, cn))
        {
            cmd.CommandType = CommandType.StoredProcedure;

            if (parameters != null)
                cmd.Parameters.AddRange(parameters);

            OdbcDataReader rdr = cmd.ExecuteReader();

            DataTable dt = new DataTable();

            dt.Load(rdr);

            return dt;
        }
    }
}

}

Answer 1

Do not instantiate the Command object and don’t define parameters on each iteration. You should try to write code as something below:

   string query = @"UPDATE bartran SET aNumberCounter = ? WHERE id = ?;";
   string cnstr=@"Driver={{MySQL ODBC 5.1 Driver}};Server=localhost;dataBase=database_name;User=root;Password=;Option=3;";
   using(OdbcConnection connection=new OdbcConnection(cnstr))
   {
    using(OdbcCommand cmd=new OdbcCommand(query,connection))
    {
    cmd.Parameters.Add("?",OdbcType.Int);
    cmd.Parameters.Add("?",OdbcType.Int);
    connection.Open();
    for (int i = 0; i < dsData.Tables["data"].Rows.Count; i++)
     {
      ...
      cmd.Parameters[0].Value=aNumberCounter;
      cmd.Parameters[1].Value=id;
      cmd.ExecuteNonQuery();
      }
    connection.Close();
    }
   }

PS: You should have to use MySql Provider API instead of Odbc API.