_ASP.NET
3351603
Assignment-3
1: List methods of Command object.
Answer:-
-The methods of Command object are given below :
1) ExecuteNonQuery() :-
-Data Manipulation tasks like Insert ,Update, Delete etc. are performed by this method.
-this method is written as command.ExecuteNonQuery();
-It returns Integer type value.
-In this Command object no of Rows affected.
2) ExecuteScalar() :-
-This method is very useful to use with Aggregate functions like (Sum, count, min, max, avg, etc.).
-This command object returns single cell.
3) ExecuteReader() :-
-This Command object is used to retrive a single value from Database after the SQL statement execution.
-To create SqlDataReader we can only use ExecuteReader method
2: What are return types of various methods of Command object?
Answer:-
-The ExecuteNonQuery() method returns an integer value.
-The ExecuteScalar() returns only single cell value.
and The ExecuteReader() returns a SqlDataReader, SqlDataReader is a forward-only, Read-only retrieval of query results from data source .
3: Write difference between DataSet and DataReader.
Answer:-
DataSet:-
-Dataset provides forward and backward access to data.
-Dataset is a disconnected architecture.
-We can do random access in Dataset.
-It is More expensive than DataReader because it stores multiple rows at the same time.
DataReader:-
-DataReader provides Forward-only and Read-only access to data.
-DataReader is a connected architecture.
4: Write example ConnectionString for MS Access and SQL Server database connectivity (total 2 separate connection string).
Answer:-
MS Access Connection String :-
Dim con As New OleDb.OleDbConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=D:\screen\anmol.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True")
Dim ad As New OleDb.OleDbDataAdapter("select * from studentdata", con)
Dim ds As New DataSet
con.Open()
ad.Fill(ds)
con.Close()
Gridview1.DataSource = ds.Tables(0)
Gridview1.DataBind()
End Sub
SQL Server Connection string:-
Protected Sub btn1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btn1.Click
Dim con As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=D:\screen\anmol.mdf; Integrated Security=True;Connect Timeout=30;User Instance=True")
Dim ad As New SqlDataAdapter("select avg(marks) from studentdata", con)
Dim ds As New DataSet
con.Open()
ad.Fill(ds)
con.Close()
Gridview1.DataSource = ds.Tables(0)
Gridview1.DataBind()
End Sub
End Class
5: List methods and properties of Connection object.
Answer:-
-The methods of connection object and its properties are given below:-
Open:- The open method opens a connection to a database for executing commands against data Source.
Syntax:- object.Open();
Close:- The Close method is used to close a Connection object, to free the system Resources..
Syntax:- Object.Open();
6: Write sample code for displaying data in GridView control of student table.
Answer:-
Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div> <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None"> <AlternatingRowStyle BackColor="White" ForeColor="#284775" /> <EditRowStyle BackColor="#999999" /> <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <PagerStyle BackColor="#284775" ForeColor="White"HorizontalAlign="Center" /> <RowStyle BackColor="#F7F6F3" ForeColor="#333333" /> <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" /> <SortedAscendingCellStyle BackColor="#E9E7E2" /> <SortedAscendingHeaderStyle BackColor="#506C8C" /> <SortedDescendingCellStyle BackColor="#FFFDF8" /> <SortedDescendingHeaderStyle BackColor="#6F8DAE" /> </asp:GridView> </div> </form></body></html>using System;using System.Collections.Generic;using System.Data;using System.Data.SqlClient;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;public partial class _Default : System.Web.UI.Page{ SqlDataAdapter da = null; DataSet ds = null; SqlConnection cn = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=Student;Integrated Security=True"); protected void Page_Load(object sender, EventArgs e) { da = new SqlDataAdapter("Select * From Studenttable", cn); ds = new DataSet(); da.Fill(ds, "Studenttable"); GridView1.DataSource = ds.Tables["Studenttable"]; GridView1.DataBind(); }}7: Write sample code for inserting data in student table using command object.
Answer:-
Public Class insert
Inherits System.Web.UI.Page
Protected Sub btn1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btn1.Click
Dim con As New OleDb.OleDbConnection("")
Dim cmd As New OleDb.OleDbCommand("insert into tablename values (1, 'anmol')", con)
con.Open()
cmd.ExecuteNonQuery()
con.Close()
Response.Write("inserted successfully")
End Sub
End Class
8: Write sample code for using average marks using executeScalar method.
Answer:-
-Public Class insert
Inherits System.Web.UI.Page
Protected Sub btn1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btn1.Click
Dim con As New OleDb.OleDbConnection("")
Dim cmd As New OleDb.OleDbCommand("select avg(marks) from studentdata", con)
con.Open()
Response.Write(cmd.ExecuteScalar() & " is the avg marks of 5 subjects")
con.Close()
Response.Write("inserted successfully")
End Sub
End Class
9: Write sample code to read data from a customer table using DataReader object.
Answer:-
Public Class insert
Inherits System.Web.UI.Page
Protected Sub btn1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btn1.Click
Dim con As New OleDb.OleDbConnection("")
Dim cmd As New OleDb.OleDbCommand("select avg(marks) from studentdata", con)
Dim dr As OleDb.OleDbDataReader
con.Open()
dr = cmd.ExecuteReader
While dr.Read
Response.Write(dr("cid") & dr("cstmrname") & dr("total") & "</br>")
End While
con.Close()
End Sub
End Class
10: Write sample code to show list of cities in a DropDownList using DataSet.
Answer:-
city.aspx
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="city.aspx.vb" Inherits="citydrop.city" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Select Country<asp:DropDownList ID="Cty" runat="server" />
</div>
</form>
</body>
</html>
city.aspx.vb
Imports System.Data.SqlClient
Public Class city
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim con As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=D:\screen\anmol.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True")
Dim ad As New SqlDataAdapter("select * from ctable", con)
Dim ds As New DataSet
con.Open()
ad.Fill(ds)
con.Close()
Cty.DataSource = ds.Tables(0)
Cty.DataTextField = "cname"
Cty.DataValueField = "cid"
Cty.DataBind()
End Sub
End Class
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