illustrates how to perform a SELECT statement using ADO.NET : Select Query « Database ADO.net « C# / C Sharp

1. C# / C Sharp
2. Database ADO.net
3. Select Query

illustrates how to perform a SELECT statement using ADO.NET

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

Publisher: Sybex;
ISBN: 0782129110
*/

/*
  Example23_1.cs illustrates how to perform a SELECT statement
  using ADO.NET
*/

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

public class Example23_1
{

  public static void Main()
  {

    // step 1: formulate a string containing the details of the
    // database connection
    string connectionString =
      "server=localhost;database=Northwind;uid=sa;pwd=sa";

    // step 2: create a SqlConnection object to connect to the
    // database, passing the connection string to the constructor
    SqlConnection mySqlConnection =
      new SqlConnection(connectionString);

    // step 3: formulate a SELECT statement to retrieve the
    // CustomerID, CompanyName, ContactName, and Address
    // columns for the first ten rows from the Customers table
    string selectString =
      "SELECT CustomerID, CompanyName, ContactName, Address " +
      "FROM Customers " +
      "WHERE CustomerID < 'BSBEV'";

    // step 4: create a SqlCommand object to hold the SELECT statement
    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

    // step 5: set the CommandText property of the SqlCommand object to
    // the SELECT string
    mySqlCommand.CommandText = selectString;

    // step 6: create a SqlDataAdapter object
    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();

    // step 7: set the SelectCommand property of the SqlAdapter object
    // to the SqlCommand object
    mySqlDataAdapter.SelectCommand = mySqlCommand;

    // step 8: create a DataSet object to store the results of
    // the SELECT statement
    DataSet myDataSet = new DataSet();

    // step 9: open the database connection using the
    // Open() method of the SqlConnection object
    mySqlConnection.Open();

    // step 10: 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");
    string dataTableName = "Customers";
    mySqlDataAdapter.Fill(myDataSet, dataTableName);

    // step 11: get the DataTable object from the DataSet object
    DataTable myDataTable = myDataSet.Tables[dataTableName];

    // step 12: 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"]);
    }

    // step 13: close the database connection using the Close() method
    // of the SqlConnection object created in Step 2
    mySqlConnection.Close();

  }

}


           
       

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