How to write data of an SQL Server table to an XML file using C#

Introduction

In this article I will discuss how to write data of an SQL server table to an XML file using C#

Description

I have an Employees table in Northwind database with some sample data that we are going to write in an XML file. You can download Northwind and pubs sample databases from here

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We will discuss two methods to convert a database table to an XML file. In first method, we will use WriteXml method of DataTable to write XML to a file. In second method we will use SELECT statement with FOR XML clause to select data from the database in XML format and then we use ExecuteXmlReader method of SqlCommand class to load XML in an XmlDocument object

Method 1:

private static void TableToXml()
{
     try
     {
          string ConString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
          string CmdString = "SELECT EmployeeID, LastName, FirstName, Title, TitleOfCourtesy, BirthDate, HireDate, Address City, Region, PostalCode, Country, HomePhone, Extension, Notes, ReportsTo, PhotoPath FROM Employees";
          SqlConnection con;
          SqlCommand cmd;
          SqlDataAdapter sda;
          DataTable dt;

          using (con = new SqlConnection(ConString))
          {
               cmd = new SqlCommand(CmdString, con);
               con.Open();
               dt = new DataTable("Employees");
               sda = new SqlDataAdapter(cmd);
               sda.Fill(dt);
               dt.WriteXml("Employees.xml");
               con.Close();
          }
     }
     catch (Exception)
     {
          throw;
     }
}

Method 2:

private void TableToXml()
{
     try
     {
          string ConString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
          string CmdString = "SELECT EmployeeID, LastName, FirstName, Title, TitleOfCourtesy, BirthDate, HireDate, Address City, Region, PostalCode, Country, HomePhone, Extension, Notes, ReportsTo, PhotoPath " +
                             "FROM Employees FOR XML RAW('Employee'), ROOT('Employees'), ELEMENTS";
          SqlConnection con;
          SqlCommand cmd;
          XmlReader reader;
          XmlDocument xmlDoc;

          using (con = new SqlConnection(ConString))
          {
               cmd = new SqlCommand(CmdString, con);
               con.Open();
               reader = cmd.ExecuteXmlReader();
               xmlDoc = new XmlDocument();

               while (reader.Read())
               {
                    xmlDoc.Load(reader);
               }

               xmlDoc.Save("Employees.xml");
          }
     }
     catch (Exception)
     {
          throw;
     }
}

Note:

By default FOR XML clause returns column’s values as attributes. ELEMENTS parameter is added to the above SELECT statement to return column’s values as elements

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