The DataSet class can be used to read a relational database table and write this table to an XML file. This article shows you how you can write data from a database to an XML file using a data set object.
You use the WriteXml method to write a dataset data to an XML file.
In this sample example, first I create a dataset connection to the Northwind database. After that, I create a data adapter object and selects all records of the Customer table. After that, I can fill a method to fill a dataset from the data adapter.
Once a dataset if filled with records, I call the WriteXml method to write data to an XML file "CustTableDt.xml" in C:\ dir.
  1. // create a connection string
  2. string connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Northwind.mdb";
  3. OleDbConnection myConnection = new OleDbConnection();
  4. myConnection.ConnectionString = connString;
  5. // create a data adapter
  6. OleDbDataAdapter da = new OleDbDataAdapter("Select * from Customers", myConnection);
  7. // create a new dataset
  8. DataSet ds = new DataSet();
  9. // fill dataset
  10. da.Fill(ds, "Customers");
  11. // write dataset contents to an xml file by calling WriteXml method
  12. ds.WriteXml("C:\\CustTableDt.xml");
Don't forget to include System.Data and System.Data.OleDb namespaces.
The portion of XML file looks like the following:
  1. <?xml version="1.0" standalone="yes" ?>
  2. - <NewDataSet>
  3. - <myTable>
  4. <CustomerID>ALFKI</CustomerID>
  5. <CompanyName>Alfreds Futterkiste</CompanyName>
  6. <ContactName>Maria Anders</ContactName>
  7. <ContactTitle>Sales Representative</ContactTitle>
  8. <Address>Obere Str. 57</Address>
  9. <City>Berlin</City>
  10. <PostalCode>12209</PostalCode>
  11. <Country>Germany</Country>
  12. <Phone>030-0074321</Phone>
  13. <Fax>030-0076545</Fax>
  14. </myTable>
  15. - <myTable>