I am unable to understand following:
$this->db->select('1', FALSE);
Can someone explain what this does and when to use it?
The first parameter is the field names or values in your case 1
from your table, the second parameter FALSE prevents the first parameter being wrapped in backticks. You'd use this is you were nesting a sub query as the first parameter.
For further information see the Codigniter docs which are incredibly useful.