Is there any way to check before call the $this->db->update() method, Is where condition set or not?

[eluser]Sarwar CSE[/eluser]
[quote author="Mirge" date="1347985483"]If you are wanting to view the query BEFORE it gets executed to check to see if a WHERE clause is found, you can use:

Code:

$query = $this->db->_compile_select();
// now you can look at $query to see if a 'WHERE' clause is found.

Note that $this->db->get() uses this method... not generally something you call directly.[/quote]
Thanks Mirge

Is there any way to extend the db class?
Like core class(Controller,Model)
Thanks
Sarwar Hasan