How to add decimal field to Codeigniter migration file?

Question

When writing codeigniter migration, I'm not sure how to proceed with adding a decimal type field. in particular, how do you determine the size of an element that is allowed? For example, how would I define an array to go to dbforge->add_field() to create a field similar to the following:

 price decimal(10,2) not null default 0.00 

Answer 1

 'price' => array( 'type' => 'DECIMAL', 'constraint' => '10,2', ), 

Answer 2

 'price' => array( 'type' => 'DECIMAL', 'constraint' => '10,2', 'null' => FALSE, 'default' => 0.00 ), 

Answer 3

 'price' => array('type' => 'DECIMAL(10,2)')