How To Create A Postgres Database Using pgAdmin

What is a Materialized View?

Android Page refresh in 20Seconds

Android Page refresh in 20 seconds

main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginLeft="23dp"
        android:text="Button" />

</RelativeLayout>

---------------------------------------------------------------------------------

MainActivity-

package com.example.pagerefresh;

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {
Handler handler;
Button b;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b=(Button)findViewById(R.id.button1);
        
        b.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "test", Toast.LENGTH_SHORT).show();
}
});
        
        Toast.makeText(getApplicationContext(), "page refreshed", Toast.LENGTH_SHORT).show();

        handler= new Handler();
      
        handler.postDelayed(new Runnable(){

            @Override
            public void run() {
                // TODO Auto-generated method stub
                Toast.makeText(getApplicationContext(), "hello1", Toast.LENGTH_SHORT).show();
              
               Intent i=new Intent(MainActivity.this,MainActivity.class);
               i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                 startActivity(i);
            handler.removeCallbacksAndMessages(null);
                handler.postDelayed(this, 4000);
            }

         }, 5000*4);//for 20sec
     
    }


@Override
public void onDestroy() {
    // TODO Auto-generated method stub
handler.removeCallbacksAndMessages(null);
    super.onDestroy();

   }

@Override
public void onStop() {
    // TODO Auto-generated method stub
handler.removeCallbacksAndMessages(null);
    super.onStop();

   }

}

Built-In Functions Of PostgreSQL

PostgreSQL built-in functions, also called as Aggregate functions, are used for performing processing on string or numeric data. Following is the list of all general purpose PostgreSQL built-in functions:

Functions	Description
COUNT	·         COUNT aggregate function is used to count the number of rows in a database table.
MAX	MAX aggregate function allows us to select the highest (maximum) value for a certain column.
MIN	MIN aggregate function allows us to select the lowest (minimum) value for a certain column.
AVG	·         AVG aggregate function selects the average value for certain table column.
SUM	·         SUM aggregate function allows selecting the total for a numeric column.
ARRAY	ARRAY aggregate function puts input values, including nulls, concatenated into an array.
Numeric	Complete list of PostgreSQL functions required to manipulate numbers in SQL.
String	·         Complete list of PostgreSQL functions required to manipulate strings in PostgreSQL.

MySQL vs PostgreSQL

Oracle and PostgreSQL Query Difference

10 Major Oracle and PostgreSQL Query Difference

Oracle	PostgreSQL
select * from tablename;	select * from tablename;
desc tablename	-----(select itself desc coming)
nvl(sum,0)	coalesce(sum,0)
decode(a,1,aa,bb)	(case when a=1 then aa else bb end)
oracle supports ‘’ or null (both are same)	In postgresql  ‘’ and null both are different
rownum	limit
rowed	ctid
Date shows dd/mmm/yyyy	yyyy/mmm/dd
Auto cast from String to Date	cast(d as date)
String to integer to_number(a)	cast ( a as numeric)

Installing and Setting up PostgreSQL