ADO.NET in ASP.net...

Hello Everybody...

We are back after holy festivals i.e. Navratri and Rama Navmi. I hope you are well and I wish the same. Goddess Durga and God Rama bless you...

Today I will explain you the most and powerful topic, which plays very main role in our data centric application in ASP.net. I know you got it, yes I am going to explain you the very most ‘ADO.NET’.

ADO.net is playing the very important role in our data centric application. It provides an API to access database systems as we program in our application. ADO (Actice Data Objects).  The .Net framework contains several namespace to access the Database objects. Below are the few one includes with ADO.NET...

System.Data.SqlClient
Contains classes for connecting to Microsoft SQL Server version 7.0 and above
System.Data.OleDb
Contains classes for connecting to a data source that has an OLE DB provider
System.Data.Odbc
Contains classes for connecting to a data source that has an ODBC driver
The System.Data.SqlClient namespace contains the following three classes:
SQLConnection:
The SqlConnection class represents an open connection to a Microsoft SQL Server data­base.

SqlCommand:

The SqlCommand class represents a SQL statement or stored procedure.

SqlDataReader:

The SqlDataReader class represents the results from a database query.
The next section of this chapter goes into the details of using each of these classes.


Instead of SQL Server if you are using a Microsoft Access database, then you will have to use the classes from the System. Data.OleDbnamespace. the System.Data.OleDb name­space includes the following classes:
OleDbConnection:
The OleDbConnection class used for Access database connection.
OledDbCommand:
The OleDbCommand class represents a Microsoft Access statement or stored procedure.
OleDbDataReader:
The OleDbDataReader class represents the results from a database query.
Below are the code, shown how to create connection string and access it through application and use of SQL Client classes..
Write the below code in web.config..under configuration section

  <connectionStrings>

    <add name="connString" connectionString="Server=local; uid=sa; pwd=pass; Initial Catalog=ved"/>

  connectionStrings>

Here is the .aspx.cs page code:

using System;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Data.SqlClient;

using System.Data.OleDb;

public partial class _Default : System.Web.UI.Page

{

    SqlConnection dbConn;

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)

        {

            try

            {

                //SqlConnection...

                dbConn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["connString"].ToString());

                lblMessage.Text = "Database server connected successfully..";

                //SqlConnection...

                SqlCommand cmd = new SqlCommand("SELECT Name, Address FROM Customer");

                dbConn.Open();

                cmd.Connection = dbConn;

                //Sql Data Reader..

                SqlDataReader dr = cmd.ExecuteReader();

                lblMessage.Text = "";   //clear the previous message..

                while (dr.Read())

                {

                    //concatenate the data...in Message Label

                   lblMessage.Text += dr["Name"].ToString();

                }

                dr.Close();

                dbConn.Close();

             

            }

            catch (Exception ex)

            {

                lblMessage.Text = "Error occured while connecting through Databsae Server.." + ex.Message;

            }

        }

    }

}

.aspx page.

<asp:Label ID="lblMessage" runat="server">asp:Label>