Yii model how to specify optional field?

Question

Yii

Hello. The following code is located in the rules of the model: array('file', 'file', 'types'=>'jpg, gif, png'),
If the field with the file is left empty in the form and the form is submitted, then the following error appears in the array of saving errors in the database [file] => Array
(
[0] => File cannot be blank .
)
this rule is.
Can you please tell me how to indicate that this field is optional and can be empty?
Thanks in advance to all who respond.

Answer 1

For a very long time I could not find a solution, so I wrote here, but after 5 minutes I still found it.
Need to specify'alloEmpty' => true