.NET & XML

Transformation

Because both the relational and hierarchical views are XML, one can be transformed into the other with an XSLT transformation. A program to transform the DataSet from one format to another is shown in Example 11-14.

Example 11-14. Program to transform a DataSet to another XML format

using System;
using System.Data;
using System.Data.SqlClient;
using System.Xml;
using System.Xml.Xsl;

public class TransformData {
  public static void Main(string [ ] args) {
    
    DataSet dataSet = new DataSet("AngusHardware");
    
    SqlConnection connection = new SqlConnection(
      "Initial Catalog=AngusHardware; Integrated Security=SSPI; User ID=sa");
    
    SqlDataAdapter customersAdapter = new SqlDataAdapter(
      "SELECT * FROM customers", connection);
    SqlDataAdapter couponsAdapter = new SqlDataAdapter(
      "SELECT * FROM coupons", connection);
    SqlDataAdapter couponRedemptionsAdapter = new SqlDataAdapter(
      "SELECT * FROM coupon_redemptions", connection);
    
    customersAdapter.Fill(dataSet, "customers");
    couponsAdapter.Fill(dataSet, "coupons");
    couponRedemptionsAdapter.Fill(dataSet, "coupon_redemptions");

    XmlDataDocument doc = new XmlDataDocument(dataSet);
    
    XmlTextWriter writer = new XmlTextWriter(Console.Out);
    writer.Formatting = Formatting.Indented;
    
    XslTransform transform = new XslTransform( );
    transform.Load("Coupons.xsl");
    transform.Transform(doc, null, writer);
  }
}

You’ve seen most of this already at one point or another. The main variation that you have not seen yet is the inclusion of several SqlDataAdapter instances ...