If you need to access tables within the same database as your Joomla! installation then you can simply use the JFactory->getDbo method. This uses the already established connection that Joomla! uses to connect to the database.<?php
$db = JFactory::getDbo();
?>
But what if you want to connect to a completely different database from the one used by Joomla!?. This might be a different database on the same machine as your Joomla! site or it might be on a different host and perhaps even require a different database driver. Well, you can do this using the JDatabase->getInstance method.
<?php
$option = array(); //prevent problems
$option['driver'] = 'mysql'; // Database driver name
$option['host'] = 'localhost'; // Database host name
$option['user'] = 'root'; // User for database authentication
$option['password'] = ''; // Password for database authentication
$option['database'] = 'another_db'; // Database name
$option['prefix'] = 'pre_'; // Database prefix (may be empty)
$db = JDatabase::getInstance( $option );
?>
$db is now an object of type JDatabase and you can perform database operations on it using the usual methods.
