Message: Undefined property: Blog::$db

[eluser]Unknown[/eluser]

Check if this is set to true in your database config file. As far as I know db->get is an active record thing, so it needs to be set to use it.

$db['default']['active_r'] = TRUE;
You can also auto load the db for each page by setting it in the autoload.php

/*
| -------------------------------------------------------------------
| Auto-load Libraries
| -------------------------------------------------------------------
| These are the classes located in the system/libraries folder
| or in your system/application/libraries folder.
|
| Prototype:
|
| $autoload['libraries'] = array('database', 'session', 'xmlrpc');
*/

$autoload['libraries'] = array('database')

Works fine, Thanx.