Pages

Backup and Restore Mysql Database using mysqldump Command

mysqldump is a effective tool to backup and restore mysql databases. Using mysqldump command we can backup one or many databases or tables.

You have to use command prompt[Windows users] or kernel[Linux users,MacOS] to backup databases.

Backup Mysql Database

  • Backup a single database
mysqldump -u root -p[root_mysql_password] [database_name] > [path_to_save_with_sql_extension]

ex:
mysqldump -u root -p123 test > D:/backups/test_backup.sql


  • Backup Multiple databases
mysqldump -u root -p[root_mysql_password] --databases [database_name] [database_name] .. > [path_to_save_with_sql_extension]

ex:
suppose we have two databases called test and tutorial
mysqldump -u root -p123 --databases test tutorial > D:/backups/test_tutorial.sql


  • Backup all the databases

mysqldump -u root -p[root_mysql_password] -all-databases > [path_to_save_with_sql_extension]

  • Backup a specific table 
Suppose we have a demo table in test database.

mysqldump -u root -p123 test demo \ > D:/backups/demotables.sql

Restore Mysql Database

To restore mysql database use following command.

mysql -u root -p[root_mysql_password] [database_name] < D:/backups/test.sql

These can be useful for backup and restore mysql databases.

Running Google App Engine in Eclipse

In this article I'm going to show you how to develop and deploy a small Java app engine application on Google App Engine using Eclipse IDE.

STEP 1
First you have to install Eclipse IDE for that . Its free so anyone can download. Here is the link.
Eclipse IDE

STEP 2
Now install Java SDK. Here is the link..
Java SDK

STEP 3
Now install the Google Eclipse App Engine plugin.
Ref Link : http://code.google.com/eclipse/docs/install-from-zip.html

STEP 4
Install the Google web toolkit plugin.
Ref Link : http://code.google.com/webtoolkit/gettingstarted.html


  • There is easiest way to follow Step 3 and 4. Click Help --> Eclipse Market Place 
  • Type Google App Engine
  • install the plugin

STEP 5
Create Web Application.

File --> New --> Web application or Simply click the g icon (blue background).


  • Enter the Project Name  as GuestBook and Package name as guestbook.
  • Make sure Google Web Toolkit checkbox and Google App Engine check box is selected.
  • Click Finish.

STEP 6
Now it will create the project structure like this.



There are some files that Eclipse automatically created.
  • src/GuestBookServlet.java
  • war/WEB-INF/web.xml
  • war/WEB-INF/appengine-web.xml 
STEP 7
After that debug your app like this. Click Run ---> Debug as ---> Web Application 
now it will create a server 8888 port so you can access it by browsing http://localhost:8888/

STEP 8
To deploy your app to Google App Engine right click the app select Google --> Deploy to App Engine




Before deploy get application ID from http://code.google.com/appengine/ .

Those are the major steps that you want to follow to create and deploy Java App Engine application to Google App Engine.

Cloud Computing

What is Cloud Computing ?
Cloud computing is location-independent computing, whereby shared servers provide resources, software, and data tocomputers and other devices on demand, as with the electricity grid.
source : http://en.wikipedia.org/wiki/Cloud_computing

Cloud Computing as the term indicates implies using the cloud infrastructure or internet based shared infrastructure to host and access applications. That means hosting application and their data on a shared servers on the internet and access the applications through a browser.

Things that cloud computing change

  • Completely shift from Desktop based model to Web based model. In cloud computing model applications are web based hosted on a cloud server and users can access the applications through a web browser. 
  • Hosting application and services. Today most business organizations host application on their servers and use their firewalls. So adding these things is a extra overhead for organizations. Moving to the cloud model make it easier to organizations.
  • Security, a key implication in cloud computing is that security risk added by the third party provider.  
Saas, Paas and Iaas

Cloud computer has various flavors of implementation. In here we talk about SaaS(Software as a Service) , PaaS(Platform as a service), IaaS(Infrastructure as a service).

Software as a Service (Saas)

This term describe software that is deployed over the internet. The services are provided with typically payment charged on monthly basis based on the number of users or services consumed. 

Platform as a service (PaaS)  

Provide the ability for building and deploying custom application on their platform. 
Amazon EC2 , Microsoft Azure , Google App Engine are some of service providers.

Infrastructure as a service (Iaas)

Provide computer and server infrastructure as a virtualization environment. 
Amazon Web Services and Rackspace are examples of service provides.

Here is the brief description about cloud computing. 

Setup Your Computer To Develop Android Applications[Windows]

In this tutorial I will show you the required steps how to setup your computer to develop Android applications in windows.

Android is a software platform and operating system for mobile devices. It based on linux kernal and it written on Java language but not use JVM to execute the applications.

Here are the requirements to setup Android in your machine.

  • Any Operating system
  • Android SDK
  • Java Development Kit
  • Eclipse IDE (Optional, but has lot of advantages)
Here are the steps that you want to follow.

STEP 1 
First you have to download the appropriate Android SDK from http://developer.android.com/sdk/index.html here.

Its free and anyone can download it. After downloading unzip it and install it. 
Now you will get the Android SDK Manager.

To get the full benefit go to Available packages and install the Third party add-ons . It includes the Google APIs.  



STEP 2
In order to run your apps you want to set the Android Path in Environment variable.
For an Example:
suppose we have Java path and Android path. So PATH variable look like this 
PATH = C:\Program Files\Java\jdk1.6.0_19\bin;C:\Program Files\Android\android-sdk-windows\tools

STEP 3

Now Every thing is set. But to develop applications you need Eclipse IDE. You can use any IDEs that support Java. But using eclipse you can get the lots of benefits. 

Download Eclipse in here ---> http://www.eclipse.org/downloads/

Goto Help --> Install New Software 
Click Add 

Enter 'ADT Plugin' for the Name and enter 'https://dl-ssl.google.com/android/eclipse/' for the URL and Select OK.

Click Next in the windows and click Finish. After that restart the Eclipse to apply the changes.



To configure Eclipse follow these steps.
1.Windows --> Preferences
2.Select Android
3.Give the SDK location and click Apply.





Now you can create any Android application in your computer.

Create Your First Mobile Application in Eclipse [J2ME]

In this tutorial I'm going to show you how to create a simple mobile application in Eclipse IDE.

First you have to download the Eclipse IDE. You do not need to pay for it, its free :)
http://www.eclipse.org/downloads/

To create mobile applications you have to download the j2me plugin.
http://eclipseme.org/

To install the plugin follow the below tutorial.
http://eclipseme.org/docs/installEclipseME.html

Now you can create any j2me mobile application in eclipse.

In here we are going to develop a simple mobile application.

STEP 1


To Create New J2ME Project
File -> New -> select j2me --> j2me Midlet suite -> click Next





Give the project name as HelloworldMobileApp and click Next

In Midlet Suite Properties use the default settings.



Click Next and Finish.

Now you can see it create your project in Project area.
STEP 2

Now select the project right click it and New --> Other



Select J2ME Midlet and click Next. Give a name for the midlet. In here i gave it as HelloworldMidlet and click finish.

It create the HelloworldMidlet class and inherit the some methods.

Now add these following code.

import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;


public class HelloworldMidlet extends MIDlet {
private Form form;
private Display display;

public HelloworldMidlet() {
form = new Form("My First J2ME App");
String msg = "Hello World";
form.append(msg);
display = Display.getDisplay(this);
display.setCurrent(form);
}

protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
notifyDestroyed();
}

protected void pauseApp() {
// TODO Auto-generated method stub

}

protected void startApp() throws MIDletStateChangeException {
// TODO Auto-generated method stub

}

}



STEP 3


We did finish coding now. But in order to run your app you have to do some configuration.

Right click the project --> Run as --> Run Configuration

Click Browse and select the project.




and Click Run

Now you can see it start the mobile device and show hello world.