using System;

using System.Data;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

​

            //for example, imagine your DB has given you this:

    var dtDb = new DataTable();

    dtDb.Columns.Add("RowId");

    dtDb.Columns.Add("DF1");

    dtDb.Columns.Add("DF2");

    dtDb.Columns.Add("DF3");

    dtDb.Rows.Add("Rowid1", "A", "B", "C");

    dtDb.Rows.Add("Rowid2", "D", "E", "F");

​

    //and your text file has given you this:

    var dtF = new DataTable();

    dtF.Columns.Add("TF1");

    dtF.Columns.Add("TF2");

    dtF.Columns.Add("TF3");

    dtF.Columns.Add("TF4");

    dtF.Rows.Add("A", "B", "C", "4");

    dtF.Columns["TF1"].ColumnName = "DF1";

    dtF.Columns["TF2"].ColumnName = "DF2";

    dtF.Columns["TF3"].ColumnName = "DF3";

    dtDb.PrimaryKey = new[] { dtDb.Columns["DF1"], dtDb.Columns["DF2"], dtDb.Columns["DF3"] };

    dtDb.Merge(dtF);

    PrintValues(dtDb, "Merged data");

​

​

}

​

private static void PrintValues(DataTable table, string label)

{

    // Display the values in the supplied DataTable:

    Console.WriteLine(label);

    foreach (DataColumn column in table.Columns)

    {

        Console.Write("{0,8}", column.ColumnName);

    }

    Console.WriteLine();

    foreach (DataRow row in table.Rows)

    {

        foreach (DataColumn column in table.Columns)

        {

            Console.Write("{0,8}", row[column, DataRowVersion.Current]);

        }

        Console.WriteLine();

    }

}

}