8dc57c0c_odeIgniter_3_0_0_documentation__Parameter
[Rule] is_unique [Description] Returns FALSE if the form element is not unique to the table and field name in the parameter. Note: This rule requires Query Builder to be enabled in order to work. [Example] is_unique[table.field] [Parameter] 
Yes
N o
Y e s
Form Validation — CodeIgniter 3.0.0 documentation
Parameter