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Thursday, February 18, 2016

How to retrieve items from database table in JAVA using Netbeans

In this article i will explain you, how to retrieve items from database table in Java using Netbeans. In previous article, we have already learned, how to create connection with the derby database using netbeans. Before reading this article, please must to see the previous article for implementations. In this article, i only explain you, how to use executeQuery( ) method and select statement in java.

--How to create connection with database full video tutorial 


 Code :

class abc {
    public abc() throws SQLException
    {
        Connection conn=DriverManager.getConnection("jdbc:derby://localhost:1527/student", "tarun", "tarun");
        System.out.println("Connection Created");
        Statement st=conn.createStatement();
        ResultSet rs=st.executeQuery("select * from USERTABLE");
        while(rs.next())
        {
            System.out.println(rs.getString(2));
        }
   
    }

}

Here, we have a table i.e USERTABLE. If you want to learn how to create table in exists database using Netbeans. Read mentioned steps:
Step-1 :  Right click on Connection String, select "connect" from popup menu.
Step-2 :  Expand username which contains Tables, views and stored procedure.
Step-3 :   Right click on table, select create table.


Write the name of table also add columns with their datatypes. 

How to use mouseenter( ) and mouseleave( ) method in JQuery

The meaning of mouse enter and mouse leave are, when your cursor enter your object bounary then mouse enter method raised similarly when your cursor goes out of your object boundary then mouse leave method raised. I will give you an example of mouse enter and mouse leave method. Lets see the example, in this, we have division, when your cursor move on your divison boundary then division background changed also text of division will be changed. This also contain mouseleave() method with the same functionality.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default22.aspx.cs" Inherits="Default22" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script src="Scripts/jquery-1.10.2.js"></script>
    <script>
        $(document).ready(function()
        {
            $('div').mouseenter(function () {
                $(this).css('background-color', 'green');
                $(this).html('MY website dotprograming.com')
            });


            $('div').mouseleave(function () {
                $(this).css('background-color', 'red');
                $(this).html('MY Blog dotprogramming.blogspot.com');
            })

        })

    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div style="height:50px;width:50px">
    Hello World !
    </div>
    </form>
</body>
</html>

Code generates the following output



Wednesday, February 17, 2016

How to create Database connection in JAVA using Netbeans

If you want to connect database with your java application then first to need a database. First to create database using Netbeans services tab. This tab available under Windows tab. You can also select this tab by using shortcut CTRL+ 5.


services tab in netbeans


  1. Expand the databases tab, select "Create Database." option. 
create database in netbeans

2. Fill fields which are shown under diagram.

Database fields in Netbeans
 3. After filling the form, you have to create database successfully.
 4. Right Click on your connection string name, select properties for copy the database URL.

java netbeans database properties

5. Copy Database URL, which is used further.

netbeans database properties
6. Create a new java project under projects tab. 
7. Add a Library in the "Libraries" section of your project.
add libraries in projects
8. Select Java DB Driver under Add Library section.

JAVA DB Drivers
9. Open your .java file which is exists in java packages folder of your project. 
10. Create a another class object, which is exists in same package.
11. Now, Open the object class, create constructor in it.
12. paste the code under the constructor.

Connection conn=DriverManager.getConnection("jdbc:derby://localhost:1527/jk", "jk", "jk");
        System.out.println("connection created"); 

Here we have three parameters in getConnection method. 
First refer to database url ; according to 5th step.
Second : Username 
Third :  password.

Tuesday, February 16, 2016

ASP.NET ListBox Insert Multiple selected item into database

In this article, I will show you how to insert multiple selected item in  database table. I have already done one projects on this topic i.e online movie ticket booking system. In this project, i selected multiple tickets by using comma symbol in TextBox. The same article i will do in different manner. In this we have a ListBox with multiple selection mode.
What i do in code behind :

  1. Store the selected of ListBox items to the string type list.
  2. For the each item, i will create a Query statement, Suppose your List contain two items i.e "Apple" and "Mango", Both are selected then use String builder class to Append Query.
  3. Like "insert into [tablename] (fruitname)values('Apple')";  and for second item  "insert into [tablename] (fruitname)values('mango')";

Source Code

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="multipleselect.aspx.cs" Inherits="multipleselect" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

    </div>
        <asp:ListBox ID="ListBox1" runat="server" Height="100px" SelectionMode="Multiple" Width="174px">
            <asp:ListItem>Apple</asp:ListItem>
            <asp:ListItem>Grapes</asp:ListItem>
            <asp:ListItem>Orange</asp:ListItem>
            <asp:ListItem>Mango</asp:ListItem>
            <asp:ListItem>Pea</asp:ListItem>
        </asp:ListBox>
        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Save" />
    </form>
</body>
</html>

Code Behind Code

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class multipleselect : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        List<string> l1 = new List<string>();
        foreach (ListItem item in ListBox1.Items)
        {
            if (item.Selected)
            {
                l1.Add(item.Text);
            }  
        }
        recordinserted(l1);
    }

  

    private void recordinserted(List<string> l1)
    {
       StringBuilder stringbi = new StringBuilder(string.Empty);
        foreach (string item in l1)
{
const string qry = "insert into [Fruits](FruitName)values";
            stringbi.AppendFormat("{0}('{1}');",qry,item);
}
        //throw new NotImplementedException();
        SqlConnection con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionStringtr"].ToString();
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.CommandText = stringbi.ToString();
        cmd.Connection=con;
        int a= cmd.ExecuteNonQuery();
        if(a>0)
        {
            Response.Write("inserted");
        }
    }
}

Code Generates the following output : 
ASP.NET ListBox Insert Multiple selected item into database

Wednesday, February 10, 2016

By using Single LINQ Query retrieve foriegn key table column

In this article, I will explain you, How to retrieve data from two joined table using single LINQ Query. Here we have two joined table in mentioned diagram. Both tables are joined from dept_no, so if you want to retrieve record from both table like:
Retrieve emp_id and emp_name who belongs to IT department.



employeeEntities empl = new employeeEntities();

            var query = from g in empl.emps
                        join m in empl.depts on g.dept_no equals m.dept_no
                        where m.dept_name == "IT"
                        select new
                        {
                            Emp_Name = g.emp_name,
                            Emp_ID = g.emp_id
                        };
               
            dataGridView1.DataSource = query.ToList();
In this code, empl is the context object through which we can access columns of both tables. emp is the foreign key table map with dept table using dept_no column. Emp_Name and Emp_ID is the reference name , which are displayed on table. Bind the query result with the dataGridView. 

Tuesday, February 9, 2016

[Solved] Rows cannot be programmatically removed unless the DataGridView is data-bound to an IBindingList that supports change notification and allows deletion.

[Solved] Rows cannot be programmatically removed unless the DataGridView is data-bound to an IBindingList that supports change notification and allows deletion. When you bind the Datagridview with List in windows form. You get error when you delete row from it. According to article title, first to implement your List from IBindingList interface, if you want to solve this issue. Suppose, you want to bind your DataGridView with this class, which is mentioned below:

public partial class userAccount
    {
        public decimal Account_No { get; set; }
        public string Name { get; set; }
         }
    }

Then you write simple code for this :

List<userAccount> ua= new List<userAccount>();
ua.Add(new userAccount(){Account_No=1000000008, Name ="Jacob"});
dataGridView1.DataSource = ua;

After binding the DataGridview, you will write the code for remove row from dataGridview.

dataGridView1.Rows.RemoveAt(dataGridView1.SelectedRows[0].Index);

After that you got error, which is mentioned below:

[Solution]

Bind DataGridView with IBindingList<userAccount> . Now the code is:

BindingList<userAccount>  bi = new BindingList<userAccount> ();
bi.Add(new userAccount(){Account_No=1000000008, Name ="Jacob"});
dataGridView1.DataSource = bi;

After binding the DataGridview, you will write the code for remove row from dataGridview.

bi.RemoveAt(dataGridView1.SelectedRows[0].Index);

Monday, February 8, 2016

Login username password saved in cookies

We all know about login form. In it, we have two fields first and second  that are username and password. Both are stored in browser memory via HttpCookie. I mean to say when you first-time login into your account your username and passwords are saved into your browser cache. So, when you come again on your website, it did not ask username and password again, redirect on home page.


Before reading this article, if you want to know about cookie then watch mentioned video.Now,  Lets start to save username and password in the cookies. 

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="logincookies.aspx.cs" Inherits="logincookies" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
        UserName :
        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
        <br />
        Password&nbsp;&nbsp; :
        <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
        <br />
        <br />
        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Login" />
&nbsp;<asp:CheckBox ID="CheckBox1" runat="server" Text="Keep Me Sign in" />
    
    </div>
    </form>
</body>
</html>

Code-Behind File 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class logincookies : System.Web.UI.Page
{
    string uname = "admin";
    string pass = "pass";
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Request.Cookies["authcookie"]!=null)
        
        {
            if (Request.Cookies["authcookie"]["username"] == uname && Request.Cookies["authcookie"]["password"] == pass)
            {
                Response.Redirect("~/mainpage.aspx");
            }
            
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        if (TextBox1.Text == uname && TextBox2.Text == pass)
        {
            if (CheckBox1.Checked)
            {
                Response.Cookies["authcookie"]["username"] = TextBox1.Text;
                Response.Cookies["authcookie"]["password"] = TextBox2.Text;
                Response.Cookies["authcookie"].Expires = DateTime.Now.AddDays(2);

            }
            Response.Redirect("~/mainpage.aspx");
            
        }
    }
}

Code Generates the following output:

Login username password saved in cookies
In this code we have a code in page load method. First to check, either Cookies are available or not. If cookies are available then check the username and password which are stored in the cookies. If both are matched then redirect to another page. When we click on button then first to match the username and password, if both are matched then saved the username and password into the cookies.


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