Using SQLite3 with CakePHP 2.0
public $default = array(
    'datasource' => 'Database/Sqlite',
    'persistent' => false,
    'host' => 'localhost',
    'login' => '',
    'password' => '',
    'database' => 'cake_blog_tutorial',
    'prefix' => '',
    //'encoding' => 'utf8',
);

public $default = array(
        'datasource' => 'Database/Sqlite',
        'persistent' => false,
        'database' => 'database_name',
        'prefix' => '',
        //'encoding' => 'utf8',
);

public $default = array(
        'datasource' => 'Database/Sqlite',
        'persistent' => false,
        'database' => ':memory:',
        'prefix' => '',
        //'encoding' => 'utf8',
);