Date Validation in Yii

public function rules()

    {

        // NOTE: you should only define rules for those attributes that

        // will receive user inputs.

        return array( 

 array('date_attribute', 'type', 'type' => 'date', 'message' => 'Please enter a valid date', 'dateFormat' => 'yyyy-MM-dd'),



 array('date_attribute', 'isDueDateGreater'),  





          );

    } 

also we can check EXPIRY DATE must Greater than START DATE
we can wirte function in our Model and use it in rules

 public function isDueDateGreater($attribute, $params) {

         if( strtotime($this->expiry_date) < strtotime($this->start_date) ){ 

        $this->addError($attribute, 'Expiry date must be greater than start date.');}

       

}