Add ADO.NET and SQL Server namespace directives to top for all following...
        using System.Data;
        using System.Data.SqlClient;

1. In Main() method...
        // Specify SQL Server specific connection string
        SqlConnection thisConnection = new SqlConnection(
            @"Data Source=(local);Integrated Security=SSPI;Initial Catalog=northwind");

        // Open connection
        thisConnection.Open();

        // Create command for this connection
        SqlCommand thisCommand = thisConnection.CreateCommand();

        // Specify SQL query for this command
        thisCommand.CommandText = "SELECT EmployeeID, LastName from Employees";

        // Execute DataReader for specified command
        SqlDataReader thisReader = thisCommand.ExecuteReader();

        //While there are rows to read
        while (thisReader.Read())
        {
            // Output ID and name columns
            Console.WriteLine("\t{0}\t{1}", thisReader["EmployeeID"], thisReader["LastName"]);
        }

        // Close reader & connection
        thisReader.Close();
        thisConnection.Close();

2. Replace assignment in "UpdatingData" class Main()...
        <s>// thisDataSet.Tables["Customers"].Rows[9]["CompanyName"] = "Acme, Inc.";</s>

        // Toggle between these two company names for exercise
        string companyNameAcme = "Acme, Inc.";
        string companyNameBottom = "Bottom-Dollar Markets";

        // Change data in Customers table, row 9, CompanyName column
        if ((string)thisDataSet.Tables["Customers"].Rows[9]["CompanyName"] == companyNameAcme)
        {
            thisDataSet.Tables["Customers"].Rows[9]["CompanyName"] = companyNameAcme;
        }
        else
        {
            thisDataSet.Tables["Customers"].Rows[9]["CompanyName"] = companyNameBottom;
        }

3. In Main(), ask for CustomerID then verify that it exists...
        Console.WriteLine("Enter five character upper case Customer ID");
        string theCustomerID = Console.ReadLine();

        if (theCustomerID.Length == 5)
        {
            // Specify SQL Server specific connection string
            SqlConnection thisConnection = new SqlConnection(
                @"Data Source=(local);Integrated Security=SSPI;Initial Catalog=northwind");

            // Create DataSet to contain related data tables, rows, and columns
            DataSet thisDataSet = new DataSet();

            // Create DataAdapter object
            SqlDataAdapter thisAdapter = new SqlDataAdapter(
                "SELECT CustomerID, CompanyName From Customers", thisConnection);
            thisAdapter.Fill(thisDataSet, "Customers");

            // Set up keys object for defining primary key
            DataColumn[] keys = new DataColumn[1];
            keys[0] = thisDataSet.Tables["Customers"].Columns["CustomerID"];
            thisDataSet.Tables["Customers"].PrimaryKey = keys;

            DataRow findRow = thisDataSet.Tables["Customers"].Rows.Find(theCustomerID);

            if (findRow == null)
            {
                // Advise user his input is bogus
                Console.WriteLine("Your requested customer ID '" + theCustomerID + "' not found");
            }
            else
            {
                // Advise user his input found a customer
                Console.WriteLine(theCustomerID + " represents NorthWind customer {0}",
                    findRow["CompanyName"]);
            }
        }
        else
        {
            // Advise user his input is dismal
            Console.WriteLine("Your input was not valid to commence search.");
        }

4. Code within the MAIN() function...
        Note that Orders SQL table has three fields with data constraints
        // Specify SQL Server specific connection string
        SqlConnection thisConnection = new SqlConnection(
            @"Data Source=(local);Integrated Security=SSPI;Initial Catalog=northwind");

        // Create DataAdapter object
        SqlDataAdapter thisAdapter = new SqlDataAdapter(
                "SELECT CustomerID,EmployeeID,OrderDate,RequiredDate," +
                "ShipVia,Freight,ShipName,ShipAddress,ShipCity,Shi pRegion," +
                "ShipPostalCode,ShipCountry From Orders", thisConnection);

        // Create the CommandBuilder object to build SQL commands
        SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);

        // Create DataSet to contain related data tables, rows, and columns
        DataSet thisDataSet = new DataSet();

        // Fill DataSet using query defined previously for DataAdapter
        thisAdapter.Fill(thisDataSet, "Orders");

        // Observe CustomerID foreign key constraint in Orders
        string customerZacheryZithers = "ZACZI";
        // Observe EmployeeID foreign key constraint in Orders
        int employeeSteveBuchanan = 5;
        // Observe ShipVia foreign key constraint in Orders
        int shipperUnitedPackage = 2;

        // New row #1
        DataRow rowOrders01 = thisDataSet.Tables["Orders"].NewRow();
        rowOrders01["CustomerID"] = customerZacheryZithers;
        rowOrders01["EmployeeID"] = employeeSteveBuchanan;
        rowOrders01["OrderDate"] = Convert.ToDateTime("2004/08/30");
        rowOrders01["RequiredDate"] = Convert.ToDateTime("2004/09/15");
        rowOrders01["ShipVia"] = shipperUnitedPackage;
        rowOrders01["Freight"] = Convert.ToDecimal("17.17");
        rowOrders01["ShipName"] = "The Shopping Center";
        rowOrders01["ShipAddress"] = "123 East Michigan Avenue";
        rowOrders01["ShipCity"] = "Paw Paw";
        rowOrders01["ShipRegion"] = "MI";
        rowOrders01["ShipPostalCode"] = "49079";
        rowOrders01["ShipCountry"] = "USA";
        thisDataSet.Tables["Orders"].Rows.Add(rowOrders01);

        // New row #2
        DataRow rowOrders02 = thisDataSet.Tables["Orders"].NewRow();
        rowOrders02["CustomerID"] = customerZacheryZithers;
        rowOrders02["EmployeeID"] = employeeSteveBuchanan;
        rowOrders02["OrderDate"] = Convert.ToDateTime("2004/09/21");
        rowOrders02["RequiredDate"] = Convert.ToDateTime("2004/10/15");
        rowOrders02["ShipVia"] = shipperUnitedPackage;
        rowOrders02["Freight"] = Convert.ToDecimal("10.12");
        rowOrders02["ShipName"] = "Jewel Supermarkets";
        rowOrders02["ShipAddress"] = "123 West Main Street";
        rowOrders02["ShipCity"] = "Dyer";
        rowOrders02["ShipRegion"] = "IN";
        rowOrders02["ShipPostalCode"] = "47923";
        rowOrders02["ShipCountry"] = "USA";
        thisDataSet.Tables["Orders"].Rows.Add(rowOrders02);

        // Write to SQL table
        try
        {
            thisAdapter.Update(thisDataSet, "Orders");
        }
        catch (System.Data.SqlClient.SqlException e)
        {
            // This is how I found out about the constraints
            Console.WriteLine("Exception is {0}", e.Message);
            return;
        }

        // Now display orders within last six months; DATEDIFF() is T-SQL function
        SqlCommand thisCommand = thisConnection.CreateCommand();
        thisCommand.CommandText =
            "SELECT OrderID, RequiredDate, ShipName, ShipAddress, " +
            "RTRIM(ShipCity) + ', ' + ShipRegion AS ShipLocale " +
            "FROM Orders WHERE CustomerID='" + customerZacheryZithers + "' AND " +
            "(DATEDIFF(day, OrderDate, GETDATE()) <= 180)";
        thisConnection.Open();

        // Load result set into the data reader
        SqlDataReader thisReader = thisCommand.ExecuteReader();
        while (thisReader.Read())
        {
            Console.WriteLine("{0}\t{1}\n{2}\n{3}\n{4}\n",
                thisReader["OrderID"], thisReader["RequiredDate"],
                thisReader["ShipName"], thisReader["ShipAddress"],
                thisReader["ShipLocale"]);
        }

        thisReader.Close();
        thisConnection.Close();

        Console.ReadLine();

5. Code within the MAIN() function...
        // Specify SQL Server specific connection string
        SqlConnection thisConnection = new SqlConnection(
            @"Data Source=(local);Integrated Security=SSPI;Initial Catalog=northwind");

        // Create DataSet to contain related data tables, rows, and columns
        DataSet thisDataSet = new DataSet();

        // Set up DataAdapter objects for each table and fill
        SqlDataAdapter supplierAdapter = new SqlDataAdapter(
            "SELECT SupplierID, CompanyName, ContactName from Suppliers",
            thisConnection);
        supplierAdapter.Fill(thisDataSet, "Suppliers");

        SqlDataAdapter productAdapter = new SqlDataAdapter(
            "SELECT SupplierID, CategoryID, ProductName from Products",
            thisConnection);
        productAdapter.Fill(thisDataSet, "Products");

        SqlDataAdapter categoryAdapter = new SqlDataAdapter(
            "SELECT CategoryID, CategoryName, Description from Categories",
            thisConnection);
        categoryAdapter.Fill(thisDataSet, "Categories");

        // Set up DataRelation between Products and Suppliers tables
        DataRelation SupplierProductRel = thisDataSet.Relations.Add("SuppProducts",
        thisDataSet.Tables["Suppliers"].Columns["SupplierID"],
        thisDataSet.Tables["Products"].Columns["SupplierID"]);

        // Set up DataRelation between Products and Categories tables
        DataRelation ProductCategoriesRel = thisDataSet.Relations.Add("ProdCategories",
        thisDataSet.Tables["Categories"].Columns["CategoryID"],
        thisDataSet.Tables["Products"].Columns["CategoryID"]);

        // Print suppliers nested products and their categories
        foreach (DataRow suppRow in thisDataSet.Tables["Suppliers"].Rows)
        {
            Console.WriteLine("Supplier: " + suppRow["CompanyName"]);
            Console.WriteLine(" Contact: " + suppRow["ContactName"]);

            foreach (DataRow prodRow in suppRow.GetChildRows(SupplierProductRel))
            {
                Console.WriteLine("\tProduct: " + prodRow["ProductName"]);

                foreach (DataRow categoryRow in prodRow.GetParentRows(ProductCategoriesRel))
                {
                    Console.WriteLine("\t Category: " + categoryRow["CategoryName"]);
                    Console.WriteLine("\t Details: " + categoryRow["Description"] + "\n");
                }
            }
        }

        Console.ReadLine();

6. Insert following just before or after the FOREACH loop region of Exercise 05...
        SupplierProductRel.Nested = true;
        // Product table is child in both relationships preventing further nesting
        <s>//ProductCategoriesRel.Nested = true;</s>
        thisDataSet.WriteXml(@"d:\temp\exercise06.xml");
        Console.WriteLine("XML table has been written!");
        Console.ReadLine();

7. Modify SQL command in "ManyRelations" with a "WHERE" clause...
                    -- AND --
        use overload of "DATACOLLECTION.ADD()" to ignore constraint
            from unmatched Orders.CustomerID values
        // Set up DataAdapter objects for each table and fill
        <s>// SqlDataAdapter custAdapter = new SqlDataAdapter(</s>
            <s>"SELECT * from Customers", thisConnection);</s>
        //Pull only customers whose names begin A through M
        SqlDataAdapter custAdapter = new SqlDataAdapter(
            "SELECT * from Customers WHERE LEFT(CustomerID, 1) <= 'M'",
            thisConnection);
        custAdapter.Fill(thisDataSet, "Customers");

        SqlDataAdapter orderAdapter = new SqlDataAdapter(
            "SELECT * from Orders",
            thisConnection);
        orderAdapter.Fill(thisDataSet, "Orders");

        // Set up DataRelation between customers and orders tables
        <s>DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",</s>
            <s>thisDataSet.Tables["Customers"].Columns["CustomerID"],</s>
            <s>thisDataSet.Tables["Orders"].Columns["CustomerID"])</s>
        DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",
            thisDataSet.Tables["Customers"].Columns["CustomerID"],
            thisDataSet.Tables["Orders"].Columns["CustomerID"],
            false);

8. Replace the SQL command in "ShowSQL" as requested...
        // Set up DataAdapter objects for each table and fill
        <s>//SqlDataAdapter thisAdapter = new SqlDataAdapter(</s>
            <s>"SELECT CustomerID from Customers", thisConnection);</s>
        SqlDataAdapter thisAdapter = new SqlDataAdapter(
            "SELECT * from Customers", thisConnection);

        ... Then run application and observe

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