DATABASE

Database concepts : issues and solutions Error 2003: Can’t connect to MySQL server on ‘local host’ (10061)

Error 2003: Can’t connect to MySQL server on ‘local host’ (10061)

Can't connect to MySQL

1. Uninstall mysql from your system
2. Delete mysql folder from c:\program files
3. Delete mysql folder from C:\Documents and Settings\All Users\Application Data for xp
4. For windows 7 C:ProgramData
5. Reinstall mysql
6. While reinstalling there will be an option for remove instance in the mysql click on it

BLOB/TEXT column 'address' used in key specification without a key length

how to establish a connection to mysql using third party api in java 

 

Establish connection in Database

 

import java.sql.*;

import java.sql.DriverManager;

public class Connector {
public static Connection connections()
{
try
{
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost/dbName","root","admin");
return con;
}
catch (Exception e)
{
e.printStackTrace();
}
return null;
}


}


insertion, delete, update mysql query example using prepared statement


import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.*;

import javax.swing.JOptionPane;

public class Ipdao
{
String splits[]=null;



public void insert(Ipmanage ipmanage) throws SQLException
{

IPmanageUI i=new IPmanageUI();
Date date=new Date(new java.util.Date().getTime());
String ipadd=ipmanage.getIpadd();

int port=ipmanage.getPortno();


Connection con=Connector.connections();
PreparedStatement p= con.prepareStatement(" insert into ipmanagetable(ipadd,port,date) values(?,?,?)");
p.setString(1,ipadd);
p.setInt(2,port);
p.setDate(3, date);
p.executeUpdate();
System.out.println(" inserted ");

JOptionPane.showMessageDialog(i," inserted");
}

public void delete(Ipmanage ipmanage) throws SQLException

{
String ipadd=ipmanage.getIpadd();

Connection con=Connector.connections();

PreparedStatement p= con.prepareStatement(" delete from ipmanagetable where ipadd=?");
p.setString(1,ipadd);
p.executeUpdate();
IPmanageUI i=new IPmanageUI();
JOptionPane.showMessageDialog(i," Deleted");


}
public void edit(Ipmanage ipmanage)
{
String ipadd=ipmanage.getIpadd();
int port=ipmanage.getPortno();
Date date=new Date(new java.util.Date().getTime());
Connection con=Connector.connections();

PreparedStatement p;
try {
p = con.prepareStatement(" update ipmanagetable(ipadd,port,date) set value(?,?,?) where ipadd=?");
p.setString(1,ipadd);
p.setInt(2,port);
p.setDate(3,date);

IPmanageUI i=new IPmanageUI();
JOptionPane.showMessageDialog(i," Edited");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

public ArrayList SearchIp(Ipmanage ipmanage)
{
//String ipadd=ipmanage.getIpadd();
ArrayList arraylist=new ArrayList();
String ipad=ipmanage.getIpadd();

Connection con=Connector.connections();
PreparedStatement p;
try {
p = con.prepareStatement("Select * from ipmanagetable where ipadd=?" );
p.setString(1, ipad);
ResultSet rs =p.executeQuery();
while(rs.next())
{
Ipmanage im=new Ipmanage();
//im.setSerialno(rs.getInt(1));

im.setIpadd(rs.getString(1));
System.out.println("found");

im.setPortno(rs.getInt(2));
im.setDate(rs.getDate(3));
im.setTime(rs.getTimestamp(4));
arraylist.add(im);

}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println(" no result");
MainFrame i=new MainFrame();
JOptionPane.showMessageDialog(i," No result found");
}

return arraylist;
}
public ArrayList Viewall()
{
//String ipadd=ipmanage.getIpadd();
ArrayList arraylist=new ArrayList();

Connection con=Connector.connections();
PreparedStatement p;
try {
p = con.prepareStatement("Select * from ipmanagetable" );
ResultSet rs =p.executeQuery();
while(rs.next())
{
Ipmanage im=new Ipmanage();
//im.setSerialno(rs.getInt(1));

im.setIpadd(rs.getString(1));

im.setPortno(rs.getInt(2));
im.setDate(rs.getDate(3));
im.setTime(rs.getTimestamp(4));
arraylist.add(im);}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return arraylist;
}
}




How google make data fetching faster ?

read more

what is amazon redshift?
Its a data ware house service  in the cloud. ( A relational OLAP - Online Analytical Processing style database)
Used to collect and store all your data and enable you to analyse it using various tools.

Where it is used?
Analyse

What is it capacity?
petabyte

How it works?
while loading data it uses a distribution key and sort key to store data in respecive nodes
a collection of node is called cluster.
once it receive a query from external tool, it creates a query plan for its node.
scalability is achieved using add or removing user nodes

Databases

1. How JDBC works