WE can easily manipulate our data from database in Joomla by using the below code. First need to call jfactory::getDBO$db = &JFactory::getDBO(); returns a reference for the database object in joomla.

For INSERT query in Joomla structure

$db = &JFactory::getDBO();
             $insertquery = "INSERT into #__TABLENAME(feild1,feild2) values('value1','value2') ";
             $db->setQuery( $insertquery );
             $db->query();

For UPDATE query in Joomla structure

     $updatequery = "UPDATE #__TABLENAME SET feild1 = 'value1' ";
     $db->setQuery( $updatequery );
     $db->query();

For DELETE query in Joomla structure

$deletequery = "DELETE FROM #__TABLENAME WHERE feild1 = 'value1' ";
         $db->setQuery( $deletequery );
         $db->query();