Database ADO.net

Reading An XML File Into A Dataset

Posted on by coder 
   


/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 * Version: 1
 */
using System;
using System.IO;
using System.Data;


namespace Client.Chapter_13___ADO.NET
{
    public class ReadingAnXMLFileIntoADataset
    {
        static void Main(string[] args)
        {
            string MyXMLDoc = @"<?xml version=&#039;1.0&#039;>?
                            <title> MyExample</title>";
            StringReader MyStringReader = new StringReader(MyXMLDoc);
            DataSet MyDataSet = new DataSet();

            MyDataSet.ReadXml(MyStringReader);
        }
    }
}

Persisting A Dataset To An XML File

Posted on by coder 
   


/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 * Version: 1
 */
using System;
using System.Data;
using System.Data.OleDb;

namespace Client.Chapter_13___ADO.NET
{
    public class PersistingADatasetToAnXMLFile
    {
        static void Main(string[] args)
        {
            OleDbConnection MyConnection = new OleDbConnection(@"Provider=Microsft.Jet.OLEDB.4.0; Data Source = c:MyAccessDB.mdb");
            OleDbDataAdapter MyAdapter = new OleDbDataAdapter("SELECT Column1, Column2, Column3 FROM MyTable", MyConnection);
            DataSet MyDataSet = new DataSet();

            MyAdapter.Fill(MyDataSet, "MyTable");
            MyDataSet.WriteXml(@"c:MyDatSet.xml");
        }
    }
}

illustrates how to write and read XML files

Posted on by coder 
   

/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy

Publisher: Sybex;
ISBN: 0782129110
*/


/*
  Example23_8.cs illustrates how to write and read XML files
*/

using System;
using System.Data;
using System.Data.SqlClient;

public class Example23_8
{

  public static void Main()
  {

    // formulate a string containing the details of the
    // database connection
    string connectionString =
      "server=localhost;database=Northwind;uid=sa;pwd=sa";

    // create a SqlConnection object to connect to the
    // database, passing the connection string to the constructor
    SqlConnection mySqlConnection =
      new SqlConnection(connectionString);

    // formulate a SELECT statement to retrieve the
    // CustomerID, CompanyName, ContactName, and Address
    // columns for the first two rows from the Customers table
    string selectString =
      "SELECT CustomerID, CompanyName, ContactName, Address " +
      "FROM Customers " +
      "WHERE CustomerID IN (&#039;ALFKI&#039;, &#039;ANATR&#039;)";

    // create a SqlCommand object to hold the SELECT statement
    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

    // set the CommandText property of the SqlCommand object to
    // the SELECT string
    mySqlCommand.CommandText = selectString;

    // create a SqlDataAdapter object
    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();

    // set the SelectCommand property of the SqlAdapter object
    // to the SqlCommand object
    mySqlDataAdapter.SelectCommand = mySqlCommand;

    // create a DataSet object to store the results of
    // the SELECT statement
    DataSet myDataSet = new DataSet();

    // open the database connection using the
    // Open() method of the SqlConnection object
    mySqlConnection.Open();

    // use the Fill() method of the SqlDataAdapter object to
    // retrieve the rows from the table, storing the rows locally
    // in a DataTable of the DataSet object
    Console.WriteLine("Retrieving rows from the Customers table");
    mySqlDataAdapter.Fill(myDataSet, "Customers");

    // get the DataTable object from the DataSet object
    DataTable myDataTable = myDataSet.Tables["Customers"];

    // use the WriteXml() method to write the DataSet out to an
    // XML file
    Console.WriteLine("Writing rows out to an XML file named " +
      "myXmlFile.xml");
    myDataSet.WriteXml("myXmlFile.xml");

    // use the WriteXmlSchema() method to write the schema of the
    // DataSet out to an XML file
    Console.WriteLine("Writing schema out to an XML file named " +
      "myXmlSchemaFile.xml");
    myDataSet.WriteXmlSchema("myXmlSchemaFile.xml");

    // use the Clear() method to clear the current rows in the DataSet
    myDataSet.Clear();

    // use the ReadXml() method to read the contents of the XML file
    // into the DataSet
    myDataSet.ReadXml("myXmlFile.xml");

    // display the columns for each row in the DataTable,
    // using a DataRow object to access each row in the DataTable
    foreach (DataRow myDataRow in myDataTable.Rows)
    {
      Console.WriteLine("CustomerID = " + myDataRow["CustomerID"]);
      Console.WriteLine("CompanyName = " + myDataRow["CompanyName"]);
      Console.WriteLine("ContactName = " + myDataRow["ContactName"]);
      Console.WriteLine("Address = " + myDataRow["Address"]);
    }

    // close the database connection using the Close() method
    // of the SqlConnection object
    mySqlConnection.Close();

  }

}

causes the the child rows to be nested within the parent rows in the output XML

Posted on by coder 
   
 

using System;
using System.Data;
using System.Data.SqlClient;

class NestedXml {
    public static void Main() {
        SqlConnection mySqlConnection = new SqlConnection("server=localhost;database=Northwind;uid=sa;pwd=sa");

        SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
        mySqlCommand.CommandText =
          "SELECT TOP 2 CustomerID, CompanyName " +
          "FROM Customers " +
          "ORDER BY CustomerID;" +
          "SELECT OrderID, CustomerID, ShipCountry " +
          "FROM Orders " +
          "WHERE CustomerID IN (" +
          "  SELECT TOP 2 CustomerID " +
          "  FROM Customers " +
          "  ORDER BY CustomerID " +
          ")";
        SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
        mySqlDataAdapter.SelectCommand = mySqlCommand;
        DataSet myDataSet = new DataSet();
        mySqlConnection.Open();
        int numberOfRows = mySqlDataAdapter.Fill(myDataSet);
        Console.WriteLine("numberOfRows = " + numberOfRows);
        mySqlConnection.Close();
        DataTable customersDT = myDataSet.Tables["Table"];
        DataTable ordersDT = myDataSet.Tables["Table1"];
        DataRelation customersOrdersDataRel =
          new DataRelation(
            "CustomersOrders",
            customersDT.Columns["CustomerID"],
            ordersDT.Columns["CustomerID"]
          );
        myDataSet.Relations.Add(
          customersOrdersDataRel
        );
        myDataSet.WriteXml("nonNestedXmlFile.xml");
        myDataSet.Relations["CustomersOrders"].Nested = true;
        myDataSet.WriteXml("nestedXmlFile.xml");
    }
}

Obtain an XML Document from a SQL Server Query

Posted on by coder

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

public class XmlQueryExample {

public static void Main() {
using (SqlConnection con = new SqlConnection()) {
con.ConnectionString = “Data Source = localhost;” +
“Database = Northwind; Integrated Security=SSPI”;
SqlCommand com = con.CreateCommand();
com.CommandType = CommandType.Text;
com.CommandText = “SELECT CustomerID, CompanyName” +
” FROM Customers FOR XML AUTO”;
XmlReader reader = null;
try {
con.Open();
reader = com.ExecuteXmlReader();
while (reader.Read()) {
Console.Write(reader.Name);
if (reader.HasAttributes) {
for (int i = 0; i < reader.AttributeCount; i++) { reader.MoveToAttribute(i); Console.Write(" {0}: {1}",reader.Name, reader.Value); } reader.MoveToElement(); } } } catch (Exception ex) { Console.WriteLine(ex.ToString()); } finally { if (reader != null) reader.Close(); } } } } [/csharp]

Fill data in DateSet to XmlDocument

Posted on by coder 
   
 

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

class UsingXmlDocument {
    public static void Main() {
        SqlConnection mySqlConnection =
          new SqlConnection(
            "server=localhost;database=Northwind;uid=sa;pwd=sa"
          );
        SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
        mySqlCommand.CommandText =
          "SELECT TOP 2 CustomerID, CompanyName, Country " +
          "FROM Customers " +
          "ORDER BY CustomerID";
        SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
        mySqlDataAdapter.SelectCommand = mySqlCommand;
        DataSet myDataSet = new DataSet();
        mySqlConnection.Open();
        mySqlDataAdapter.Fill(myDataSet, "Customers");
        mySqlConnection.Close();
        XmlDocument myXmlDocument = new XmlDocument();
        myXmlDocument.LoadXml(myDataSet.GetXml());
        Console.WriteLine("Contents of myXmlDocument:");
        myXmlDocument.Save(Console.Out);
        foreach (XmlNode myXmlNode in myXmlDocument.SelectNodes("/NewDataSet/Customers")) {
            Console.WriteLine("CustomerID = " + myXmlNode.ChildNodes[0].InnerText);
            Console.WriteLine("CompanyName = " + myXmlNode.ChildNodes[1].InnerText);
            Console.WriteLine("Country = " + myXmlNode.ChildNodes[2].InnerText);
        }
        XmlNode myXmlNode2 = myXmlDocument.SelectSingleNode("/NewDataSet/Customers[CustomerID=" ANATR"]");
        Console.WriteLine("CustomerID = " + myXmlNode2.ChildNodes[0].InnerText);
        Console.WriteLine("CompanyName = " + myXmlNode2.ChildNodes[1].InnerText);
        Console.WriteLine("Country = " + myXmlNode2.ChildNodes[2].InnerText);
    }
}

Update Data Using Sql Statements 2

Posted on by coder 
   


/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 * Version: 1
 */
using System;
using System.Data;
using System.Data.SqlClient;

namespace Client.Chapter_13___ADO.NET
{
    public class UpdatingDataUsingSqlStatements
    {
        static void Main(string[] args)
        {
            SqlConnection MyConnection = new SqlConnection(@"Data Source=(local); Initial Catalog = CaseManager; Integrated Security=true");

            MyConnection.Open();

            String MyString = "UPDATE Test SET Contact = &#039;Lee&#039;";
            SqlCommand MyCmd = new SqlCommand(MyString, MyConnection);

            MyCmd.ExecuteScalar();
            MyConnection.Close();
        }
    }
}