This tutorial should provide you with the basics of what you need to know to use the Joomla! database libraries.

The easiest way to get a database object is by getting the system database object returned by the JFactory class. The static method JFactory::getDBO() returns a singleton instance of the system database object regardless of scope and is the recommended way of getting this object.

// This gets the database object using the JFactory class
$db = &JFactory::getDBO();

Joomla! 1.5 introduces the concept of database drivers which will allow you to get database objects that point to different database sources.

// Create a new database object
$myDB = new JDatabase::getInstance( $options );

For the purposes of this tutorial we will use a very simple database table that stores information about dogs. The database table has a dog_id field with a unique integer id field, a name field and a color field for each dog. To keep things simple we have only added three dogs to our database table:

Dog 1 is named Spot and is white.

Dog 2 is named Fido and is brown.

Dog 3 is named Buster and is also brown.

The following table represents our database table which we will simply call, dogs.

<informaltable> <tgroup cols=”3”> <thead> <row> <entry align=”center”>dog_id</entry> <entry align=”center”>name</entry> <entry align=”center”>color</entry> </row> </thead> <tbody> <row> <entry>1</entry> <entry>Spot</entry> <entry>white</entry> </row> <row> <entry>2</entry> <entry>Fido</entry> <entry>brown</entry> </row> <row> <entry>3</entry> <entry>Buster</entry> <entry>brown</entry> </row> </tbody> </tgroup> </informaltable>

Lets say for example that I want to find out the name of the second dog in my database table. This is a fairly straightfoward task, I simply need to get the name value in the name field where the dog_id is 2 so lets build an SQL query to do that.

SELECT name FROM dogs WHERE dog_id = 2

Easy enough, now we need to actually get the value using our database object.

First we need to get ourselves a database object that is connected to the database our dogs table is in.

// Get the system database object.
$db = &JFactory::getDBO();

Next we need to set our query to the database object. To do this we will use the setQuery method.

// Set our query to the database object.
$db->setQuery( 'SELECT name FROM dogs WHERE dog_id = 2' );

Lastly we call the loadResult() method.

// Use the loadResult() method to get only the first value from the first row of the result set.
$name = $db->loadResult();