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Contents 1 Introduction 2 Installation 2.1 Installing MySQL 2.2 Installing JDBC 3 Testing 3.1 Creating the test database 3.2 Creating the test program 3.3 Running the Program

[edit] Introduction

This document describes how to set up your Arch system so MySQL Databases can be accessed via Java programs.

[edit] Installation

[edit] Installing MySQL

To start with, switch to the system user, then install MySQL.

su (enter your system password)
pacman -S mysql

There are now two "fixes" you have to make. Firstly edit the file my.conf to allow network access

gedit /etc/my.cnf

Find the line with skip_networking in and comment it out so it looks like this

#skip-networking

Close that file, and edit the /etc/hosts.allow file

gedit /etc/hosts.allow

and enter on a blank line

mysqld : ALL : ACCEPT

Finally start mysql up with :

/etc/rc.d/mysqld start

[edit] Installing JDBC

JDBC is not currently in the repositories. I downloaded the current version, at the time of writing 5.06 from the MySQL website at http://www.mysql.com/products/connector-j/

Next, unpack it into a temporary directory

cd /tmp
tar xzvf /aux/arch/extras/mysql-connector-java-5.0.6.tar.gz (the exact filename will depend on where you download it to)

Finally, copy it into the java extensions directory

 cp mysql-connector-java-5.0.6-bin.jar /opt/java/jre/lib/ext/

[edit] Testing

To access mysql's command line tool,

mysql

[edit] Creating the test database

The following commands create a database and allow a user 'paulr'. You will need to change the user name to whatever yours is.

create database emotherearth;
grant all privileges on emotherearth.* to paulr@localhost identified by "paulr";
flush privileges;

Now press Ctrl+D to exit the command line tool.

[edit] Creating the test program

Use an editor to create a file DBDemo.java with the following code in it. You will need to change the username and password appropriately.

import java.sql.*;
import java.util.Properties;
public class DBDemo
{
 // The JDBC Connector Class.
 private static final String dbClassName = "com.mysql.jdbc.Driver";
 // Connection string. emotherearth is the database the program
 // is connecting to. You can include user and password after this
 // by adding (say) ?user=paulr&password=paulr. Not recommended!
 private static final String CONNECTION =
                         "jdbc:mysql://127.0.0.1/emotherearth";
 public static void main(String[] args) throws
                            ClassNotFoundException,SQLException
 {
   System.out.println(dbClassName);
   // Class.forName(xxx) loads the jdbc classes and
   // creates a drivermanager class factory
   Class.forName(dbClassName);
   // Properties for user and password. Here the user and password are both 'paulr'
   Properties p = new Properties();
   p.put("user","paulr");
   p.put("password","paulr");
   // Now try to connect
   Connection c = DriverManager.getConnection(CONNECTION,p);
   System.out.println("It works !");
   c.close();
   }
}

[edit] Running the Program

To compile and run the program enter

javac DBDemo.java
java DBDemo

and hopefully, it should print out

This is the database connection
com.mysql.jdbc.Driver
It works !